text:
|Publication number
|Publication type
|Application number
|Publication date
|Feb 12, 1985
|Filing date
|Oct 12, 1982
|Priority date
|Oct 12, 1982
|Fee status
|Also published as
|Publication number
|Harold R. Schnetzka, Frank E. Wills, Dean K. Norbeck
|Original Assignee
|Borg-Warner Corporation
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (6), Non-Patent Citations (4), Referenced by (21), Classifications (10), Legal Events (9)
|External Links: USPTO, USPTO Assignment, Espacenet
This invention relates to a control system for regulating the conduction angles of a network of SCR's (silicon controlled rectifiers) to vary the power translated from a three-phase A-C power source to a load circuit, while at the same time protecting the control system against undesired signal components in the three phase voltages that may otherwise preclude accurate control over the power delivered to the load circuit.
When the load circuit must be powered by an adjustable amplitude d-c voltage, such as is the case, for example, when the load takes the form of an inverter which in turn operates an a-c motor, the SCR network may comprise a three-phase full wave rectifier bridge having three pairs of SCR's, to each of which pairs is applied a respective one of the three alternating phase voltages provided by the three-phase A-C power supply and received from the power supply over three line conductors. The conduction angles of the six SCR's are controlled in order to establish at the output of the bridge a d-c voltage of a desired magnitude and to control the power supplied through the inverter to the a-c motor. More specifically, the power flow is adjusted by regulating the conduction angles of the SCR's during each half cycle of the applied a-c line voltage. Each SCR can conduct, during each half cycle of the voltage applied thereto from the three-phase A-C power source, when the SCR's anode is positive relative to its cathode. However, conduction will not occur during a half cycle until gate current is supplied to the SCR's gate. At that instant, the SCR fires into conduction, or turns on, and permits load current to flow therethrough until the end of the half cycle at which time the anode-cathode voltage will be zero and the anode will no longer be positive with respect to the cathode. "Conduction angle", as used herein and in the appended claims, means the time during which any SCR is actually conducting (the "on time") during a 180� half-cycle of a supply voltage. The greater the angle or time delay between the start of a half cycle and the firing of the SCR into conduction, the less the conduction angle and the less alternating current that will be rectified and translated to the load circuit, namely, through the inverter to the a-c motor, thereby providing less d-c voltage across the output of the three-phase full wave rectifier bridge.
If controlled a-c power must be translated to a three-phase load, such as a three-phase a-c motor, a three-phase A-C switch may be utilized to vary the magnitude of the three alternating currents which flow to that load. Such a switch also includes three pairs of SCR's, each pair being connected in a respective one of the three line conductors over which the three phase voltages are received from the A-C power supply. By regulating the conduction angles of the six SCR's, the three alternating load or phase currents, supplied to the three-phase a-c motor, may be established at a desired level.
Regardless of the particular construction of the SCR network which adjusts the power flow, it is imperative that the gating signals for the SCR's be generated by circuitry which operates in precise synchronism with respect to the instants at which the phase voltages cross their a-c axis and thus have a zero instantaneous amplitude. The instants at which the SCR's are fired into conduction must be closely controlled and must be synchronized or keyed to the zero voltage points or crossings which will always occur at the same frequency and with the same time spacing or period from one zero crossing to the next, even though the phase voltages may not be perfectly sinusoidal in shape and may be contaminated with undesired harmonics, noise, transients or other distortion components. Unless the development of the gating signals for the SCR's is exactly synchronized to the zero voltage crossings of the three phase voltages, the timing of those gating signals will be incorrect and the SCR's will be triggered into conduction at the wrong times, resulting in an erroneous and undesired level of power flow to the load circuit. When the power flow cannot be properly regulated and held at a desired level, the reliability and performance of the entire system suffers substantially. Such misfiring of the SCR's can be caused by distortion components in the phase voltages. The gating may be too advanced or too retarded. If a relatively small conduction angle is required to achieve the desired power flow, the SCR's should be gated on near the end of each half cycle. A retarded gating signal could even allow gating near the start of the next half cycle, and this would effect much advanced gating for that next half cycle with a resultant surge in power flow which may damage or destroy some of the circuit components (such as the switching devices in an inverter) in the load.
Unfortunately, the previously developed SCR control systems for controlling the flow of three-phase A-C power are plagued by this problem. Such prior systems require relatively "clean" and sinusoidal shaped line voltages to operate properly. Distortion components on the power line deleteriously affect the operation of those prior systems to the extent that they cannot even be used in many power distribution systems where the three-phase line voltage is subject to distortion components.
This problem has been overcome by the present invention. The disclosed control system ensures that line voltage disturbances and distortions will not affect the power flow to the load circuit. The present invention provides a highly reliable control system which is immune to three-phase A-C power line distortions.
Previously-developed SCR control systems for three-phase power develop the gating signals for each phase by means of circuitry which is driven or operated only by that phase. In other words, individual and independently operated control circuits are employed for each of the three phase voltages, thereby requiring three complete and separate control circuits each having the same construction and each being controlled by a different one of the three phase voltages. In accordance with another aspect of the invention, a significant improvement over these prior systems is achieved in that a substantial portion of the control system is common to all three phases and yet is controlled by only one of the phase voltages. This results in a very efficient system, being considerably simpler and less expensive in construction and employing many fewer circuit components than the previous systems.
The control system of the present invention controls the conduction angles of three pairs of SCR's (connected in the form of either a three-phase full wave rectifier bridge or a three-phase A-C switch), to each of which pairs is applied a respective assigned one of the three alternating sinusoidal phase voltages of a three-phase A-C power supply, in order to regulate the power flow from the power supply to a load circuit, which receives d-c power from the bridge configuration and a-c power from the switch configuration. The control system comprises means for developing, from a predetermined one of the alternating phase voltages, a reference waveform having amplitude excursions which are precisely synchronized to the zero voltage crossings of the predetermined phase voltage, despite the presence of any undesired harmonics, noise, transients or other distortion components in that phase voltage. There are means for developing, from the reference waveform, three phase-displaced square waves each of which effectively represents a respective assigned one of the three phase voltages and has amplitude excursions precisely synchronized to the zero voltage crossings of its assigned phase voltage. A d-c control voltage is provided which represents a desired power flow to the load circuit. Finally, the control system includes means responsive to the three square waves and to the d-c control voltage for producing gating signals for triggering the six SCR's into conduction at the angles necessary to deliver the desired power flow to the load circuit.
The features of the invention which are believed to be novel are set forth with particularity in the appended claims. The invention may best be understood, however, by reference to the following description in conjunction with the accompanying drawings in which:
FIG. 1 schematically illustrates a control system, constructed in accordance with one embodiment of the present invention, and the manner in which that control system controls an SCR network to regulate the power translated from a three-phase A-C power supply to a load circuit, the SCR network taking the form of a three-phase full wave rectifier bridge;
FIG. 2 illustrates a three-phase A-C switch and the manner in which it may be substituted for the rectifier bridge in FIG. 1; and,
FIG. 3 depicts various voltage signal waveforms that will be helpful in understanding the operation of the three-phase control system. The voltage waveforms are identified by letter designations and the points or conductors in FIG. 1 where these various voltages appear are indicated by corresponding letters.
In FIG. 1 line conductors L1, L2 and L3 connect to a conventional three-phase A-C power supply 8 which may be the usual A-C power mains, and thus provide three-phase a-c voltage, namely three alternating voltages varying in sinusoidal fashion and having the same amplitude and frequency but being phase-displaced with respect to each other by 120�. The frequency of the supply voltage will depend on the geographic area where the A-C power supply is provided (the frequency will usually be either 50 or 60 cycles per second or hertz), and the magnitude of the a-c line voltages may take any appropriate value depending on the characteristics of the load to be energized or driven. For convenience, the three phase voltages are designated phases A, B and C (or φA, φB and φC) as indicated by the labels associated with the three line conductors L1, L2 and L3 over which the three-phase power is received. Since there is no neutral line conductor from the A-C power supply, each of the phase voltages is actually a line-to-line voltage and appears on one of the line conductors L1, L2 and L3 relative to another one of the line conductors. This is made clear by the sine waves illustrated at the top in FIG. 3. Each of the three higher amplitude sinusoidal waveforms drawn in full-line construction depicts one of the three phase voltages. The associated labels indicate the line conductor where each phase voltage is found, or measured, together with the reference line conductor. Specifically, the leading phase voltage in point of time may be considered phase A or φA and is marked AB, meaning the voltage found on line conductor L1 relative to that on line conductor L2. Lagging by 120� is sinusoidal voltage waveform BC (phase B or φB) which is that appearing on conductor L2 with respect to conductor L3. Lagging the phase voltage BC by 120� is phase voltage CA (phase C or φC), measured at line conductor L3 as referenced to conductor L1. Of course, 180� counterparts for these phase voltages may be found by inverting the measurements, namely by observing the voltages on line conductors L2, L3 and L1 relative to conductors L1, L2, and L3, respectively. The phase inverted voltages, shown in FIG. 3 in dashed line construction, are appropriately labeled BA, CB and AC.
The primary windings of wye-connected transformer 10 are connected to the three line conductors so as to produce, across secondary winding 10a, the line-to-neutral voltage for phase A. This sinusoidal-shaped voltage is measured at the upper or ungrounded terminal of winding 10a relative to the ground plane, which will be zero volts, and is drawn in FIG. 3 and labeled AN, meaning phase A referenced to neutral or ground. As is well known, such a line-to-neutral voltage will lag its associated line-to-line phase voltage by 30� and will have an amplitude substantially less than the line-to-line voltage. Specifically, the line-to-neutral voltage will have an amplitude 1/1.732 times that of the associated line-to-line voltage. Although only line-to-neutral voltage AN is needed to operate the control system of the invention, as will be made apparent, the other two line-to-neutral voltages BN and CN for phases B and C, respectively, are illustrated in FIG. 3 and will be very helpful in gaining a complete understanding of the operation of the invention. If desired, the BN and CN voltages, which may be derived from the φB and φC primary windings of transformer 10, may be employed for other functions, such as checking phase rotation or sequence and phase loss.
The sinusoidal voltage AN is applied to band-pass filter 12 which is tuned to the fundamental frequency of the three-phase A-C power supply. It will be assumed, in the illustrated embodiment, that that frequency is 60 hertz. The band-pass filter introduces no phase shift whatsoever to the fundamental but attenuates both high and low frequencies. The output voltage of filter 12 will thus be the same as voltage AN and will be exactly in phase therewith. If there are any undesired distortion components in phase A, such as harmonics, noise, transients, etc., those components would appear in voltage AN but would be removed by filter 12 so that its output signal would be "clean" and sinusoidal shaped. Of significant importance is the fact that the zero voltage crossings in the filter's output signal will be exactly in phase with the zero voltage crossings of the line-to-neutral fundamental voltage AN. Preferably, filter 12 is constructed by cascading low-pass and high-pass filters, with the high-pass filter preceding the low-pass filter. Since voltage AN is illustrated in FIG. 3 as being perfectly sinusoidal and distortion-free, that waveform also depicts the voltage appearing at the output of band-pass filter 12 and is so indicated in FIG. 1.
The output of filter 12 is applied to a squaring amplifier 13, preferably taking the form of a schmitt trigger, which effectively detects the zero voltage crossings of the sinusoidal voltage AN and converts that voltage to a voltage of square waveform as illustrated by waveform D in FIG. 3. The output square wave voltage D of squaring amplifier 13 is in exact phase with voltage AN in that the amplitude excursions of waveform D occur in precise time coincidence with the zero voltage crossings of voltage AN. Since the zero voltage crossings of voltage AN lag the corresponding crossings of phase voltage AB by exactly 30�, the amplitude excursions of voltage waveform D are precisely keyed or synchronized to the zero voltage crossings of phase voltage AB. Moreover, since there is a fixed phase relationship between all three of the line-to-line phase voltages and all three of the line-to-neutral voltages, regardless of the presence of undesired distortion components in any of those voltages, the amplitude excursions of waveform D will also be synchronized to the zero voltage crossings of the four voltages BC, CA, BN and CN. It will therefore be appreciated that the amplitude excursions of waveform D can be employed to determine the timing of the zero voltage crossings of those four voltages. In other words, waveform D contains enough information to effectively represent all of the phase voltages and, as will be made apparent, this will permit the development of precisely timed gating signals for all six of the SCR's in the three-phase full wave rectifier bridge 15 illustrated in FIG. 1, the output of which bridge powers a load circuit 14 which may, for example, comprise an inverter which in turn drives an a-c motor. There will be no need to develop and to employ voltages BN and CN, but as will be seen the appearance of waveforms BN and CN in FIG. 3 will assist in obtaining a complete understanding of the invention. Since square wave D constitutes the basic reference to which all of the other signals in the control system are keyed or synchronized, waveform D will be termed the "reference waveform".
To produce the required gating signals, the voltage represented by reference waveform D is applied to a first input of a phase locked loop 16 whose output is connected through an inverter 17 and a pair of series-connected divide-by-2 counters 18 and 19 to the input of a divide-by-6 ring counter 21, an output of which is connected back to a second input of phase locked loop 16. Suitable counters, for counters 18 and 19, may be found in an integrated circuit made by Motorola under the designation MC14013BCL. An integrated circuit, designated CD4076BF and manufactured by RCA, may be employed to function as ring counter 21. Phase locked loop 16 essentially includes a phase detector coupled through a lag-lead filter to a voltage controlled oscillator and is manufactured as an integrated circuit by Motorola under the designation MC14046BCL and by RCA under the designation CD4046BF. A phase locked loop functions to maintain the phase and frequency of the signal on its second (or feedback) input exactly like the phase and frequency of the signal on its first input, regardless of what countdown takes place in the feedback loop. When the signal on the first input is a square wave having a 50% duty cycle, as is the case with waveform D, the signals on the two inputs of a phase locked loop will be identical in every respect, namely, waveshape, phase and frequency. In effect, the signal waveform on the first input is "cloned" on the second or feedback input. No matter what occurs in the feedback loop between the output of the phase locked loop and its second input, the signal on the second input will always be the same as the signal on the first input when the first input signal has a 50% duty cycle. The output signal of the phase locked loop will, however, be determined by counters 18, 19 and 21 in the feedback loop. With those counters producing a total division of 24, the frequency of the output signal of phase locked loop 16 will be 24 times the frequency of the signal denoted by waveform D, namely, 60�24 or 1440 hertz and these relatively high frequency pulses will have a 50% duty cycle like the pulses of reference waveform D. This 1440 hertz output signal is shown by waveform E in FIG. 3 and the high frequency pulses of that signal may be referred to as "timing pulses" since they are employed, as will be explained, in producing the gating signals to achieve precise firing of the six SCR's in rectifier bridge 15.
Considering one full cycle (positive and negative excursions) of a voltage waveform such as AN or D occurring over 360�, it is to be noted that a positive-going timing pulse of waveform E occurs every 15�, with each pulse having a duration of 7.5�. Observe also that the phase locked loop ensures that a timing pulse will occur immediately before each zero voltage crossing of each of the line-to-neutral voltages AN, BN and CN. The trailing edges of those pulses will occur in exact time coincidence with the associated zero crossings. This is clearly seen for voltage AN by comparing waveform E with reference waveform D whose amplitude excursions occur at the zero crossings of voltage AN. It will thus be apparent that the periodically recurring timing pulses of voltage waveform E are precisely related in frequency and phase to each of the three phase voltages and to each of the three line-to-neutral voltages. The timing pulses will be exactly synchronized to the zero crossings of those six sinusoidal voltages.
Inverter 17 inverts the phase of the timing pulses so that the 180� counterpart of waveform E (namely, E) will be applied to the input of divide-by-2 counter 18, the output signal of which is illustrated by waveform F. Divide-by-2 counter 19 produces, from waveform F, the signal of waveform G for application to the input of divide-by-6 ring counter 21. In response to that input signal, ring counter 21 develops at its three outputs the three phase-displaced (by 120�) square waves Ha, Hb and Hc, each having a frequency of 60 hertz. Square wave Ha is applied to the second or feedback input of phase locked loop 16 and, as mentioned hereinbefore, will be identical in every respect to the reference waveform D applied to the first input of circuit 16. This absolute identity is clearly seen by comparing waveforms Ha and D in FIG. 3. Hence, square wave Ha bears the same information as waveform D. Specifically, the amplitude excursions of waveform Ha will occur in exact time coincidence with the zero voltage crossings of voltage AN and will lag the zero crossings of phase voltage AB by 30�. Waveform Ha is thus synchronized to and effectively represents phase voltage AB or phase A. Since square wave Hb lags square wave Ha by precisely 120�, the amplitude excursions of square wave Hb will occur in exact time coincidence with the zero voltage crossings of line-to-neutral voltage BN which in turn lag the zero crossings of phase voltage BC by 30�. Square wave Hb therefore represents phase voltage BC or phase B. It will also be apparent that the amplitude excursions of square wave Hc occur in time coincidence with the zero crossings of line-to-neutral voltage CN and are therefore synchronized to the zero crossings of phase voltage CA. Square wave Hc consequently represents phase voltage CA or phase C.
It will now be appreciated that by using only one phase signal (phase A) as a reference, three phase-displaced square wave signals Ha, Hb and Hc have been generated which effectively represent the three phases, each being a squared up representation of a respective assigned one of the three phase voltages. This is a salient feature of the invention. All of the described timing circuitry is only tied to one phase and yet all three phases will be controlled. Obviously, this unique approach results in substantial circuit economies since considerably fewer circuit components are needed compared to prior systems. Furthermore, any undesired distortion components in any of the three phase voltages are effectively rendered harmless. By eliminating the phase A undesired components in filter 12 and then producing the three square waves Ha, Hb and Hc from the output of the filter, the control system is made immune to the distortion components in all three phases.
As mentioned, a positive-going timing pulse of waveform E occurs immediately before each zero crossing of voltages AN, BN and CN and thus just before the amplitude excursions of square wave voltages Ha, Hb and Hc. One of those voltage pulses will occur every 60� and they are selected by AND gates 23 and 24. More particularly, AND gate 23 receives the phase inverted or 180� counterparts of waveforms F and G (namely, F and G) and produces therefrom pulses for application to one of the inputs of AND gate 24, whose other input receives the timing pulses of waveform E. Hence, any time waveforms F and G are both at their relatively low levels (signals F and G thereby being at their relatively high levels), a positive-going timing pulse of waveform E will be developed at the output of AND gate 24, as illustrated by waveform J in FIG. 3.
Meanwhile, exclusive NOR gates 25, 26 and 27 produce, from square wave signals Ha, Hb and Hc, the signals of waveforms Ka, Kb and Kc, respectively. An exclusive NOR gate produces a relatively low level output (logic 0) if one of its two inputs is at a relatively high level (logic 1) while its other input is logic 0. In other words, when either input is logic 1, but not both, the output will be logic 0. If both inputs are the same (either logic 0 or logic 1), the output will be relatively high or logic 1. Thus, each positive-going pulse of waveform Ka occurs when both of waveforms Ha and Hb are at the same logic level, either logic 1 or logic 0. Similarly, the positive-going pulses of waveform Kb occur when square waves Hb and Hc are the same, and the positive-going pulses of waveform Kc occur when square waves Hc and Ha are at the same level.
AND gates 31, 32 and 33 employ respective ones of signals Ka, Kb and Kc to select pulses from waveform J, thereby producing the signals of waveforms Ma, Mb and Mc at the outputs of gates 31, 32 and 33, respectively. It will be observed that the positive-going pulses of waveform Ma occur just before an amplitude excursion of square wave Ha, while the pulses of waveforms Mb and Mc occur immediately prior to amplitude excursions of square waves Hb and Hc, respectively. The signals of waveforms Ma, Mb and Mc are consequently phase displaced from each other by 120� and each is associated with a respective one of the three phases, the pulses of each wave-form periodically recurring at twice the frequency of the A-C power supply 8. As will be made apparent, the pulses of waveforms Ma, Mb and Mc are employed to generate ramp-shaped signals and are appropriately called "ramp reset signals". The circuitry provided by gates 23-27 and 31-33 is thus labeled "ramp reset logic 28".
Suitable ramp forming circuits may fulfill the functions of circuits 34, 35 and 36 to generate, under the control of the ramp reset signals Ma, Mb and Mc, the three phase-displaced, ramp-shaped signals Na, Nb and Nc, each of which has a frequency of 120 hertz and is associated with or related to an assigned respective one of the three phases. One such ramp forming circuit is shown and described in detail in U.S. Pat. No. 4,315,305, issued Feb. 9, 1982 in the name of Edward C. Siemon, and assigned to the present assignee. Note that each of the ramp-shaped pulses of waveform Na extends substantially throughout, and occurs in time coincidence with, an entire half cycle of the associated line-to-neutral voltage AN. In like manner, the ramp-shaped pulses of waveforms Nb and Nc extend throughout, and occur during, the half cycles of the associated voltages BN and CN, respectively.
The ramp-shaped signals Na, Nb and Nc are applied to the inverting or (-) inputs of respectives ones of voltage comparators 37, 38 and 39, to the non-inverting or (+) inputs of which is applied a d-c control voltage whose magnitude represents a desired power flow from the A-C power supply 8 and through the rectifier bridge 15 to the load circuit 14. Of course, the d-c control voltage may be provided by any appropriate source. It may, for example, be derived from a simple potentiometer which is adjusted to change the level of the control voltage when the power flow to the load is to be changed, or the d-c control voltage may take the form of an error voltage derived by effectively comparing the actual d-c voltage at the output of bridge 15 with a desired set point voltage, the error voltage automatically changing any time a correction is needed to return the d-c voltage back to the desired level. A control arrangement, in which such an error voltage is developed, is illustrated in the aforementioned U.S. Pat. No. 4,315,305. The d-c control voltage, applied to comparators 37, 38 and 39, may also be developed by sensing some parameter or characteristic of the load circuit in order to automatically control the power delivered through rectifier bridge 15 in response to, and under control of, that sensed information.
The amplitude level of the d-c control voltage, regardless of where it is at any given time, will fall somewhere within the amplitude range covered by the ramp-shaped pulses of waveforms Na, Nb and Nc. For convenience of illustration and explanation, the d-c control voltage has been superimposed in dashed construction on the ramp-shaped signals in FIG. 3. As will be seen, the particular amplitude of the d-c control voltage selected for illustration will result in a relatively low magnitude D-C output voltage from rectifier bridge 15 and a corresponding relatively low power flow to load circuit 14.
At the beginning of a cycle of waveform Na when a ramp-shaped pulse is just starting to decrease, the voltage at the (-) input of comparator 37 will be greater than (or positive with respect to) the d-c control voltage at the comparator's (+) input, resulting in a relatively low level output voltage as shown by waveform Oa. At some point during the cycle, as determined by the magnitude of the d-c control voltage, the ramp voltage will drop below the d-c control voltage and comparator 37 will abruptly switch from a low level to a high level output voltage where it will remain until the end of the ramp and the end of the cycle (as shown in waveform 0a), whereupon the comparator returns to its low level output voltage. The leading edge of each positive-going pulse in waveform Oa is therefore adjustable or variable in time within a half cycle of line-to-neutral voltage AN, as determined by the amplitude of the d-c control voltage, whereas the trailing edge of each Oa pulse is fixed and will always occur when voltage AN completes a half cycle and crosses its a-c axis. Thus, if the amplitude of the d-c control voltage is increased, the positive-going pulses of waveform Oa become wider and their leading edges are shifted to the left in FIG. 3. Conversely, if the control voltage level is lowered, the Oa pulses become narrower and their leading edges move to the right in FIG. 3. In any event, the trailing edges of the Oa pulses are always in time coincidence with the zero voltage crossings of voltage AN.
In like fashion, comparator 38 switches from a low level output to a high level output at the instant that each ramp-shaped pulse of waveform Nb decreases to the level of the d-c control voltage and stays at the high level until the termination of the ramp, thereby generating the positive-going pulses of waveform Ob at the output of comparator 38. The leading edge of each Ob pulse is adjustable in time, as determined by the control voltage, and occurs during a half cycle of voltage BN, while the trailing edge of each of those pulses is fixed and occurs when voltage BN completes the half cycle and crosses zero voltage. Similarly, comparator 39 responds to the d-c control voltage and to the ramp-shaped signal Nc and develops the positive-going pulses of waveform Oc, whose leading edges occur some time during the half cycles of line-to-neutral voltage CN and whose trailing edges occur in time coincidence with the zero voltage crossings of voltage CN. Of course, with the described arrangement the three phase-displaced signals Oa, Ob and Oc will all be absolutely identical in wave shape and frequency (120 hertz). In a manner to be explained, the positive-going pulses of waveforms Oa, Ob and Oc are eventually distributed or channeled to the gates of the six SCR's of bridge 15 to provide the gating signals for triggering the SCR's into conduction at the angles necessary to deliver the desired power flow to load circuit 14. For this reason, the pulses of waveforms Oa, Ob and Oc will be referred to as "gating pulses".
By observing the sinusoidal waveforms depicting the three phase voltages in FIG. 3, it is evident that the anodes of the six SCR's are established at voltages more positive than that on their associated cathodes at six different time intervals during a complete cycle of the three-phase A-C source. Moreover, it will be appreciated that every time an SCR is turned on to permit current flow in the direction from the SCR's anode to its cathode, another SCR in the rectifier bridge must also be fired into conduction to complete a conduction path for the load current. The gating pulses of waveforms Oa, Ob and Oc therefore must be combined and supplied to the appropriate SCR's to achieve the required gating.
To this end, steering logic circuitry (circuits 41, 42 and 43), comprising conventional AND gates and inverters, effectively separates and steers the gating pulses (waveforms Oa, Ob and Oc) from the three comparators 37, 38 and 39 to the six outputs of the logic circuitry, three of the outputs providing the gating pulses occurring during the positive half cycles of respective ones of the three line-to-neutral voltages AN, BN and CN, while the other three outputs provide the gating pulses occurring during the negative half cycles of respective ones of the three line-to-neutral voltages, the gating pulses at each output thereby occurring at the same frequency as the line-to-neutral voltages. In short, each of signals Oa, Ob and Oc is effectively divided into two signals. To elucidate, steering logic circuit 41 operates in response to the gating pulses of waveform Oa and to square wave Ha to produce, at the upper output of circuit 41, only the Oa pulses that occur when square wave Ha is at its low voltage level. Those selected gating pulses are depicted by waveform A+ in FIG. 3. The intervening pulses of waveform Oa, that occur when square wave Ha is at its high voltage level, are selected by circuit 41 and produced at the circuit's lower output, as indicated by waveform A- in FIG. 3. Steering logic circuit 42 functions in similar manner in response to square wave Hb and to the gating pulses of waveform Ob to provide the pulses of waveform B+ at the circuit's upper output and the pulses of waveform B- at the lower output. Waveforms Hc and Oc operate steering logic circuit 43 so as to develop the pulses of waveform C+ at the circuit's upper output and the pulses of waveform C- at the lower output.
The six outputs of the steering logic circuits 41, 42 and 43 are applied to the inputs of the six OR gates 51-56 in order to produce the six gating signals illustrated by waveforms GA+, GB+, GC+, GA-, GB- and GC- in FIG. 3. More particularly, OR gate 51 combines the gating pulses of waveforms A+ and C- to develop the GA+ gating signal. Gate 52 effectively adds the A- pulses and the B+ gating pulses to provide the gating signal of waveform GB+. The B- pulses and the C+ pulses are ored in gate 53 to generate the GC+ gating signal. The A- pulses and the C+ pulses are combined by gate 54 to provide the GA- gating signal. OR gate 55 adds the B- and A+ gating pulses to develop the GB- gating signal. Finally, the gating pulses of waveforms C- and B+ are combined by OR gate 56 to produce the gating signal of waveform GC-. Note that each of the OR gates 51-56 receives the gating pulses occurring during the positive half cycles of one of the line-to-neutral voltages AN, BN and CN and also the gating pulses occurring during the negative half cycles of one of the other line-to-neutral voltages, each of the six or gates thereby producing a pair of gating pulses during each cycle. As will be appreciated, such double pulsing is employed so that at least two of the SCR's of bridge 15 are fired into conduction simultaneously to provide a complete conduction path through the bridge for the load current.
SCR gate drivers 61-66 connect to the outputs of respective ones of OR gates 51-56 to produce appropriate gating current for the SCR's in response to the gating voltage signals developed at the outputs of the gates. Specifically, each of the six gate drivers 61, 62, 63, 64, 65 and 66 is connected to the gate of a respective one of the six SCR's A+, B+, C+, A-, B- and C- in bridge 15. The timing of the gating current supplied by the gate drivers is, of course, controlled by the six gating signals of waveforms GA+, GB+, GC+, GA-, GB- and GC-. Consequently, those waveforms will indicate the instants at which the SCR's are triggered into conduction. By comparing the six gating signal waveforms, GA+ through GC-, it will be realized tha every time gating current is translated to the gate of SCR A+ to trigger that SCR into conduction, gating current is simultaneously delivered to either the gate of SCR B- or to the gate of SCR C-. Similarly, when a gating pulse is applied to SCR B+ to fire that SCR into conduction, a gating pulse is simultaneously applied to either SCR A- or SCR C-. Furthermore, when SCR C+ is gated into conduction, gating current is supplied at the same time to either SCR A- or SCR B-. All of this simultaneous gating is required so that complete conduction paths will exist for the load current through bridge 15.
Considering now the specific example illustrated by the gating signal waveforms in FIG. 3, in response to the leading edge of the first-occurring gating pulse (labeled 68) in waveform GC+, gating current will be fed to SCR C+. At that same instant, the leading edge of the first-occurring complete gating pulse (designated 69) in waveform GA- causes the translation of gating current to the gate of SCR A-. At that time, line conductor L3 will be positive relative to line conductor L1 (as shown by phase voltage CA in FIG. 3), the anodes of both SCR's C+ and A- thereby being positive with respect to their cathodes. The SCR's will thus be fired into conduction, conducting load current as long as their anodes remain positive relative to their cathodes, namely as long as the SCR's remain in a forward biased state. Of course, this interval will be relatively short since phase voltage CA is only about 24� away from completing a positive half cycle when SCR's C+ and A- begin conducting. The SCR's will continue to conduct during that 24� interval until the half cycle is completed, at which time the voltage across both of the SCR's drops to zero and the SCR's are no longer forward biased. Hence, for the example shown, each of SCR's C+ and A- will have a conduction angle of approximately 24�. During that conduction angle power will flow to load circuit 14, load current being translated in the direction from conductor L3 through SCR C+ and load circuit 14 and then back through SCR A- to conductor L1.
When phase voltage CA crosses zero and SCR's C+ and A- cease conducting load current, power flow to the load circuit will be temporarily arrested. It will resume, however, in response to the leading edge of pulse 71 in waveform GC+ and to the leading edge of the first-occurring pulse 72 in waveform GB-. At that instant, line conductor L2 will be negative relative to line conductor L3 (as shown by phase voltage BC) or, viewed differently, conductor L3 will be positive with respect to conductor L2 as indicated by waveform CB shown in dashed construction in FIG. 3. Gating pulse 71 therefore triggers C+ into conduction and the concurrently-occurring pulse 72 gates SCR B- into conduction, causing load current to flow in the direction from conductor L3 through SCR C+ and load circuit 14 and then back through SCR B- to conductor L2. Of course, the conduction angle of each of those SCR's will also be about 24�, terminating when phase voltage BC reaches zero volts.
Once again power flow to the load will be temporarily halted, but will resume in response to the leading edges of the concurrently-occurring pulses 73 and 74 in waveforms GA+ and GB-, respectively, which turn on SCR's A+ and B- at an instant during a positive half cycle of phase voltage AB when line conductor L1 is positive relative to line conductor L2. Load current thus flows in the direction from conductor L1 through SCR A+ and load circuit 14 and then back through SCR B- to line conductor L2, this current continuing to flow during the 24� interval during which SCR's A+ and B- are established in their forward biased conditions, namely until phase voltage AB drops down to zero volts.
Upon the termination of current flow through SCR's A+ and B-, power flow to the load is withheld until the occurrence of the leading edges of the concurrently-occurring pulses 75 and 76 in waveforms GA+ and GC-, respectively, which gate SCR's A+ and C- into conduction at a time during a negative half cycle of phase voltage CA when conductor L3 is negative relative to conductor L1 or, viewed differently, when conductor L1 is positive relative to conductor L3, as indicated by waveform AC shown in dashed construction in FIG. 3. Load current consequently flows from conductor L1 and through SCR A+, load circuit 14 and SCR C- to conductor L3 until phase voltage CA reaches zero volts.
It will now be apparent that pulse 77 in waveform GB+ and pulse 78 in waveform GC- trigger SCR's B+ and C- into conduction during a positive half cycle of phase voltage BC when conductor L2 is positive relative to conductor L3, causing load current to flow in the direction from conductor L2 and through SCR b+, load circuit 14 and SCR C- to conductor L3. To complete a cycle of operation, gating pulses 79 and 81 of waveforms GB+ and GA-, respectively, fire SCR's B+ and A- into conduction during a negative half cycle of phase voltage AB when conductor L1 is negative relative to conductor L2 or, stated differently, when conductor L2 is positive relative to conductor L1 (see dashed waveform BA). Load current will be translated in response to the gating pulses, and during the 24� conduction angle, from conductor L2 and through SCR B+, load circuit 14, and SCR A- to conductor L1.
It will now be understood that when increased power flow to the load is desired, the leading edges of all of the pulses in the six gating signal waveforms GA+-GC- will be advanced in time (namely will move to the left in FIG. 3), while their trailing edges will remain fixed. Each gating pulse therefore increases in width, but only to the left in FIG. 3, as the conduction angle is increased. When the conduction angle of each SCR is increased to about 36� of each half cycle of each phase voltage, the double pulses of the gating signal waveforms will merge or overlap, as a result of which single and relatively wide gating pulses will be applied to the SCR's for medium to relatively large conduction angles. The relatively low 24� conduction angle, employed in the operational description of the invention, was selected so that double pulses would be included in the gating signals.
The gating current signals developed by gate drivers 61-66 may be supplied, without any alteration or modification whatsoever, to the six SCR's of the three-phase A-C switch 85 in FIG. 2 to regulate the flow of alternating load current from the three-phase A-C power supply 8 to three-phase load circuit 86. A-C switch 85 is of conventional construction and may be employed in any control system where it is desired to control the translation of three-phase current to a load. For example, such an A-C switch is utilized in U.S. Pat. No. 4,057,842, issued Nov. 8, 1977, in the name of Bruce K. Bauman et al, and assigned to the present assignee. In that patent, the load comprises a three-phase a-c motor which may function as the compressor motor in a large capacity air-conditioning system.
While particular embodiments of the invention have been shown and described, modifications may be made, and it is intended in the appended claims to cover all such modifications as may fall within the true spirit and scope of the invention.
|Cited Patent
|Filing date
|Publication date
|Jan 5, 1976
|Oct 11, 1977
|Dumas Guy H
|Master-slave control method and device for a multiphase circuit
|Sep 12, 1979
|Feb 9, 1982
|Borg-Warner Corporation
|Controlled D-C power supply
|Feb 13, 1981
|Mar 15, 1983
|Borg-Warner Corporation
|Protection system for immunizing an inverter system against A-C line voltage disturbances
|Aug 6, 1981
|May 24, 1983
|Michael J. Piperides
|Golf stance and swing practice device
|Aug 9, 1982
|Jul 31, 1984
|Litton Industrial Products, Inc.
|Timing generator for use with multi-phase control rectifier systems
|May 18, 1982
|Aug 7, 1984
|Mitsubishi Denki Kabushiki Kaisha
|Gate pulse phase shifter
|Alden et al., "Thyristor DC Motor Drive with Single Phase Locked Equidistant Pulse Generation", Canadian Communications and Power Conference, Montreal, Canada (Oct. 15-17, 1980).
|Alden et al., Thyristor DC Motor Drive with Single Phase Locked Equidistant Pulse Generation , Canadian Communications and Power Conference, Montreal, Canada (Oct. 15 17, 1980).
|Int. J. Electronics, vol. 47, No. 2, pp. 139 145, Aug. 1979.
|Int. J. Electronics, vol. 47, No. 2, pp. 139-145, Aug. 1979.
|Citing Patent
|Filing date
|Publication date
|Dec 10, 1982
|Apr 29, 1986
|U.S. Philips Corporation
|Control signal generator arrangement for semiconductor switches
|Feb 27, 1987
|Oct 4, 1988
|Asea Power Systems, Inc.
|Inverter commutation failure prevention method and apparatus
|Dec 3, 1987
|Jan 10, 1989
|Sundstrand Corp.
|Multiple phase rectifier with active filter for removing noise in triggering signals and digital phase shift compensator for phase shifting signal passed through
|Dec 29, 1988
|Sep 5, 1989
|York International Corporation
|Control for three terminal power semiconductor devices
|Oct 4, 1990
|May 18, 1993
|International Business Machines Corporation
|Digital phase match discriminator for three-phase power
|Nov 2, 1992
|Nov 16, 1993
|Tecumseh Products Company
|Protection circuit in inverter for refrigerators
|Sep 3, 1996
|Aug 10, 1999
|Mercury Electric Corporation
|Harmonic correction of 3-phase rectifiers and converters
|Mar 31, 1997
|Nov 30, 1999
|Gec Alsthom Limited
|Control arrangement for a multilevel convertor
|Nov 2, 2000
|Aug 21, 2001
|General Electric Company
|System and method for compensating for voltage notches in two-phase phase locked loops
|Feb 6, 2003
|Jan 4, 2005
|Zippy Technology Corp.
|Multi-period cycle-alternative switching mode power supply control device
|Jan 8, 2003
|Feb 13, 2007
|Micromed Technology, Inc.
|Method and system for detecting ventricular collapse
|Nov 10, 2004
|May 29, 2007
|Zippy Technology Corp.
|Multi-period cycle-alternative switching mode power supply control device and its control method
|Sep 22, 2005
|Oct 7, 2008
|Denso Corporation
|Exhaust gas-driven generator system and method of controlling electrical system
|Feb 6, 2003
|Aug 12, 2004
|Chin-Wen Chou
|Multi-period cycle-alternative switching mode power supply control device
|Jan 8, 2003
|Jan 6, 2005
|Morello Gino F.
|Method and system for detecting ventricular collapse
|Nov 10, 2004
|Mar 24, 2005
|Zippy Technology Corp.
|Multi-period cycle-alternative switching mode power supply control device and its control method
|Nov 29, 2004
|Jul 7, 2005
|Xingwu Wang
|Markers for visualizing interventional medical devices
|Oct 27, 2004
|Jul 7, 2005
|Xingwu Wang
|Implantable medical device
|Sep 22, 2005
|Jun 1, 2006
|Denso Corporation
|Exhaust gas-driven generator system and method of controlling electrical system
|Feb 15, 2012
|Dec 27, 2012
|Noel Johnson
|Equalization of the current in a three-phase electrical power system
|Nov 23, 1988
|Jun 15, 1989
|Sundstrand Corporation
|Converter for converting a multiple phase variable frequency ac voltage into dc
|U.S. Classification
|363/129, 323/320, 323/326, 363/87
|International Classification
|Cooperative Classification
|European Classification
|Jan 17, 1983
Owner name: BORG-WARNER CORPORATION; 200 SO. MICHIGAN AVE., CH
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:SCHNETZKA, HAROLD R.;WILLS, FRANK E.;NORBECK, DEAN K.;REEL/FRAME:004081/0027
Effective date: 19821006
|Feb 4, 1987
Owner name: YORK INTERNATIONAL CORPORATION, 631 SOUTH RICHLAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. EFFECTIVE;ASSIGNOR:BORG-WARNER CORPORATION;REEL/FRAME:004676/0360
Effective date: 19860609
|Apr 15, 1988
|Fee payment
Year of fee payment: 4
|May 2, 1989
Owner name: CANADIAN IMPERIAL BANK OF COMMERCE
Free format text: SECURITY INTEREST;ASSIGNOR:YORK INTERNATIONAL CORPORATION;REEL/FRAME:005156/0705
Effective date: 19881215
|Jan 31, 1992
Owner name: CANADIAN IMPERIAL BANK OF COMMERCE
Free format text: SECURITY INTEREST;ASSIGNOR:YORK OPERATING COMPANY, F/K/A YORK INTERNATIONAL CORPORATION A DE CORP.;REEL/FRAME:005994/0916
Effective date: 19911009
|Feb 4, 1992
Owner name: CANADIAN IMPERIAL BANK OF COMMERCE
Free format text: SECURITY INTEREST;ASSIGNOR:YORK INTERNATIONAL CORPORATION (F/K/A YORK OPERATING COMPANY);REEL/FRAME:006007/0123
Effective date: 19911231
|Apr 27, 1992
|Fee payment
Year of fee payment: 8
|Jul 8, 1992
Owner name: CANADIAN IMPERIAL BANK OF COMMERCE
Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:YORK INTERNATIONAL CORPORATION, A DE CORP.;REEL/FRAME:006194/0182
Effective date: 19920630
|Feb 12, 1996
|Fee payment
Year of fee payment: 12


text:
1200 Reviews
$1000 Protection*
I was very pleased with my purchase and highly recommend this company to anyone needing a part for their Masterbilt smoker.
Nla leg 1 2lgslt kd eur blk
Leg 1" 2lgslt kd eur blk - this part is no longer available
Arkla: A24AE
Sunbeam: A240E A240F A240K A240N A240N-5 A24CE N240W
This part may fit other models. Please contact us if you require additional assistance.
Our warehouse is stocked full of parts for all kinds of appliances.
Questions? Just ask - No call centers!
We are a USA business based in Denver, Colorado and we stand fully behind our products and service

subset: commoncrawl


text:
Beautiful sunrise and view! LIKED !!! Best wishes! Yuri.
Thanks for the info. Glad Guy is still around - nothing new on Panoramio for several years.
Wonderful presentation by night of this beautiful palace! Greetings.
Nice pano.Compliments. Like e Fav.
LIKE ! Greetings from Ukraine! Yuri.
Pekné zachytenie L.
Zdravím Jaro
I think your younger brother shared the same name as me. I was at the South School and I think you would have lived in Queen Street at the time. Strangely enough I was living in O'Connor/Willagee for a while just a few years ago. O'Connor of course did the harbour stone works in both locations, the harbour moles would have been getting extended during your time in NZ. You may remember the big Lima crane and the heavy trucks using Mill St. Certainly a small world and I enjoyed seeing the pics.
LOL, Norrel - Freud is finding your comment 'Very Interesting!' ;) (As does U2 :D )
mignon ,mignon!!!!!!!!
Another fine capture Cal. Very likeable.
Cheers, Herb


text:
Relevant offers
Skipper Brendon McCullum looked notably downbeat after New Zealand won the Hamilton Twenty20 match against England with their most comprehensive performance in recent memory.
Similarly, he shrugged his shoulders and offered a half-smile before trying to explain away his side's heavy defeat in the series decider on Friday.
Twenty20 internationals are like that. Aside from anything untoward happening off the field involving cash and shady characters (and there's no suggestion there was here), how can you explain the disparity of results from Auckland, to Hamilton, to Wellington in matches involving largely the same personnel?
The side who gain an early edge in the first 10 overs invariably ride their momentum to the end.
Asked to assess how the T20 sides stacked up after such a one-sided affair, McCullum said it was a head-scratcher.
"It's hard to look at it and say if we had done something better would it have made a difference. It's a real tough one to analyse because we were just poor across the board, and they were excellent across the board, hence the gulf between the two teams."
The same could have been said in reverse after Hamilton when New Zealand dominated, via McCullum's bat and the bowling of Mitchell McClenaghan and Ian Butler, who were welcome additions.
That pair were then sent into orbit in Wellington, but only had 139 to defend, as opposed to 192.
"The bowlers throughout this series have tried incredibly hard. Mitchell McClenaghan still kept coming in hard for us," McCullum said.
"We tried to use him in that attacking mode, but when they've got the freedom to play like that, they were able to up the ante and put us under pressure.
"There was some excellent hitting. We served them up a bit with the ball skidding on. We bowled too straight and our seamers weren't able to get any swing."
The series went to rankings, with England arriving fourth in the world and New Zealand eighth. New Zealand are a handy T20 side, but struggle to string them together.
England, the 2010 world champions, have enough good players to focus on a specialist T20 side with a different captain, Stuart Broad, who was also the player of the series.
Alex Hales and opening partner Michael Lumb, who hit nine sixes between them in blasting 143-0 off 12.4 overs at the Cake Tin, are T20 specialists.
Jos Buttler, the biggest hitter, is in the ODI squad but made his name in the shortest format, while Jade Dernbach also returns home but was a handy foil for senior quicks Broad and Steven Finn, all going at 140kmh.
- Sunday Star Times
Sponsored links
Mark Reason: No-one cares what the Warriors do off the pitch, as long as they deliver on it
Warriors 'could have died' mixing prescription drugs with energy drinks - doctor
Parramatta Eels docked 12 NRL points over salary cap breach
Leicester City win maiden English Premier League title
Is Leicester City's 5000:1 upset the greatest sporting shock ever?
A year after mega fight, could Floyd Mayweather Jr and Manny Pacquiao do it again?
Super Rugby Power Rankings - week 10
Super Rugby sensation Damian McKenzie re-signs with Chiefs for two years
Cronulla Sharks centre Gerard Beale called into Kiwis' starting side to play Kangaroos
Jamie Vardy's rags to riches rise a victory for the dreamers
Ruthless Mark Selby stays strong to win world snooker championship final
Team New Zealand wary of tricky conditions as America's Cup returns to New York
Stormers winger Leolin Zas gets two week ban for dangerous tackle on Bernard Foley
Parramatta Eels set to plummet down the NRL ladder in salary cap breach penalty
Pregnant woman killed in Northland crash
Mark Reason: No-one cares what the Warriors do off the pitch, as long as they deliver on it
When is 'New Zealand made' not really NZ made?
Owner tracks missing iPad as it enjoys its own vacation across the US
Parramatta Eels docked 12 NRL points over salary cap breach
Woman's big Mother's Day surprise: A 5.9kg baby
Jets scrambled as UK plane alters course and goes quiet
Warriors 'could have died' mixing prescription drugs with energy drinks - doctor
The New Zealand beach town that's better than the Caribbean
Kiwis now buy more SUVs than cars
Prime Minister John Key says lawyer's email was 'sloppily written'
A year after mega fight, could Floyd Mayweather Jr and Manny Pacquiao do it again?
When is 'New Zealand made' not really NZ made?
Mark Reason: No-one cares what the Warriors do off the pitch, as long as they deliver on it
Auckland student's creative approach to campaigning for melanoma drug Keytruda
Children aged 10 and 12 missing overnight in Wairarapa
Mediaworks dumps FOUR for new reality channel Bravo
The New Zealand beach town that's better than the Caribbean
Dying tavern owner still waiting for the right price
Coroner tells health board to improve its policies after inquest into suicide
Manu Vatuvei's bizarre message amid Warriors prescription drug revelations
Leicester City win maiden English Premier League title
Captain Cook's Endeavour, on which he explored New Zealand, found off USA
Dead fish desecrate Zahra Baker memorial
Princess Charlotte's first birthday gifts revealed - including All Blacks merchandise
Should bouncers be banned from cricket?


text:
Connecting travelers with local guides.
Worldwide. Since 2008.
Guides in
Travelers Served!
Auckland Shore Excursions
advanced search
view guides
Experience Auckland through the eyes of a local private guide! Browse our tour 'suggestions' - each can be customized just for you.
Shore Excursion Tours
Auckland Private Shore Excursions
Experience a unique Auckland shore excursion with a friendly personal guide from
. Your private tour guide knows the Auckland area as only locals do, and is eager to show you New Zealand's exciting "City of Sails," in a flexible tour that highlights your travel interests.
Discover the vibrant blend of Polynesian, European and Asian cultures that make this city by the bays such a fascinating place to visit, especially with a local guide who knows the
best-kept secrets
of the city behind the must-see sights of Auckland.
In your time ashore, you can see spectacular scenery from North Head, get the inside story on local history, shop your way through Takapuna's boutiques and relax on the beach with a view of dormant Rangitoto, the volcanic island.
Book an Auckland shore excursion tour offered by ToursByLocals, and ask your personal guide about customizing your private tour to include exactly what you want to see and do.
Go global — tour by local!
Tour Guide Legal Requirements
In New Zealand there is no requirement for a guide to have a license to give tours.
However, if the tour guide is also the driver, then they are required to hold a Passenger Service License and have a Private Hire Registration.
The driver must hold a Passenger Endorsement and must also complete a log book, and must record all work time. Drivers must not exceed the allowable work time.
The vehicle must hold a Certificate of fitness (CoF)
Some rental vehicles are not suitable as Passenger Service vehicles due to the narrow aisle space, seating arrangements and lack of cargo barriers. Most rental company contracts forbid the vehicle being used in a passenger service.
report error
All ToursByLocals guides have met our
ToursByLocals Guide Requirements
which includes warranting that they can legally give the tours they offer.
Deboarding Requirements
Citizens of many countries do not require a visa to enter New Zealand.
Visit the
New Zealand Government Website
for more details.
Auckland Shore Excursion Tours
Spectacular Auckland City & Country - Private Tour
A day tour combining Auckland City, Coast and Country
learn more»
Wild West Coast Private Tour
Half Day Excursion - Revel in the Natural Environment Away From Crowds
learn more»
Auckland in a Day with a private guide
Perfect for cruise ship passengers
learn more»
Waiheke Island Paradise Private Tour
Wine tasting and lunch in boutique Waiheke Wine Region
learn more»
City & Country Wine & Cheese Private Tour
Spectacular City views , the best of Kumeu's historic wineries, fine cheeses and a superb lunch
learn more»
Auckland Escape - Private Tour
See, taste, smell Auckland with a Private Guide
learn more»
Auckland - City to Surf
Highlights of Auckland and the West
learn more»
Auckland Shore Excursion Tours...
Why Book Through ToursByLocals?
about ratings
Tour in Tauranga, New Zealand:
"Doug has proved to be a consummate professional tour guide with his wide knowledge of the environmental policies of NZ,,..."
Sinh Tran - Dec, 2014
Tour in Auckland, New Zealand:
"Our tour guide, Claire, was excellent. Under difficult circumstances, she provided an interesting, informative and enjo,..."
Bobbie G. - Nov, 2015
Tour in Auckland, New Zealand:
"Louise is the most knowledgeable, gracious, entertaining, generous tour guide we have used. You can not go wrong with L,..."
Patt Brust - Feb, 2016
[view guide page]
Choose your own guide
. See their photos, read their bios and communicate with them prior to booking your tour.
It's more affordable than you might think
. Our pricing is per-tour NOT per-person so if there are 3 or more in your group, you'll probably pay less than if you took a big bus tour.
Every tour is private
. Your guide will spend time only with you and the people you're traveling with.
Go at your own pace
. See as much as you can or slow things down to a saunter. With your private guide, your day is flexible.
Benefit from a local's knowledge
. Access more intimate, out of the way spots that have never seen a bus tour.
Every tour is customizable
. See the sights YOU want, try the food YOU crave, learn about what interests YOU the most.
Questions? Talk to a REAL person
. Our customer support team offers reliable, friendly service plus a 24 hour emergency hotline.
Traveler Login
Guide Login
Travel Agent Login
Terms & Conditions
Privacy Policy
Cancellation Policy
ToursByLocals BLOG
Contact ToursByLocals
Copyright © 2008, 2016 ToursByLocals, All Rights Reserved.


text:
Recorded on August 25, 2011
From the Heritage Foundation, I'm Ernest Istook.
A recent White House announcement shows that what government gives with one hand, it takes away with the other. The President bragged that he's getting rid of unnecessary regulations that cost us $2-billion a year.
Every bit helps, but simultaneously they're adding 75 new major regulations last year and this year, which are an annual $40-billion drag on the economy.
So for every dollar the White House reduced regulations, it added $20 of new red tape. We get $2-billion in relief, but $40-billion in new costs, which make it tougher for business to create more jobs.
But it gets even worse. Almost 3-thousand more rules and regulations are in the pipeline—especially from Obamacare--that will add billions more of job-killing red tape.
I guess this is what they call a balanced approach—everytime they do something right, they compensate by doing something wrong.
Distinguished Fellow
Fox News contributor and decorated Iraq and Afghanistan war veteran Pete Hegseth resurrects Theodore Roosevelt's famous Citizenship in a Republic address – best known for — Read more
Escalating extremist violence in Bangladesh, including multiple murders of liberal activists and writers and attacks on foreigners and members of religious minorities, is causing alarm — Read more
Everywhere militants were blowing up Christians, their churches, their shops. They threatened them with kidnapping. They promised to take their children. The message to these — Read more
The Master Plan analyzes the Russian government's propaganda war in Europe, as particularly waged in the Baltics, to destabilize Western social and political institutions there. — Read more
The Constitution of the United States begins with the words: We the People. But from the earliest days of the American republic, there have — Read more
Co-hosted byDuring his trip to India two weeks ago, U.S. Defense Secretary Ashton Carter met with his Indian counterpart Defense Minister Manohar Parrikar for the — Read more
On February 13, 2016, Americans lost a legal titan with the passing with Justice Antonin Scalia. Conservatives mourn the loss of a standard-bearer and liberals — Read more
Co-hosted byRussian aggression, Iranian adventurism, Chinese land reclamation, and Middle Eastern instability pose a growing threat to U.S. allies and interests. At the same — Read more
Co-hosted byOriginally published following the Supreme Court's landmark Kelo v. New London decision, Cornerstone of Liberty: Property Rights in 21st Century America made a powerful — Read more
The Heritage Foundation is the nation's most broadly supported public policy research institute, with hundreds of thousands of individual, foundation and corporate donors. Heritage, founded in February 1973, has a staff of 275 and an annual expense budget of $82.4 million.
Our mission is to formulate and promote conservative public policies based on the principles of free enterprise, limited government, individual freedom, traditional American values, and a strong national defense. Read More
Receive updates from Heritage about current events and initiatives in your email inbox
Already Signed up?
© 2016, The Heritage Foundation Conservative policy research since 1973


text:
Impressionist lulz!
RECOMMEND: Follow RUBEN BOLLING on TWITTER.
RECOMMEND: Follow RUBEN BOLLING on TWITTER.
Tom the Dancing Bug, IN WHICH we bring to the attention of all our readers the illegal, disgusting, unspeakable satirical insults besetting Turkey's President Recep Erdogan. (With illustrations!)
Tom the Dancing Bug, IN WHICH Nate the Right Pundit bravely asserts that the Science just isn't settled yet, on such pressing issues as global warming and his acute appendicitis.
Tom the Dancing Bug, IN WHICH the omnipotent God-Man battles the very human Human-Man to a standstill!
Why buy one of those expensive and confusing universal remotes, clogged with enough buttons to launch a space shuttle, when you could accomplish the same electronic control right on your favorite mobile device? The Blumoo Universal Remote, now just $52.99 in the Boing Boing Store, harnesses the audio power of all your household equipment right […]
You may not love Microsoft Word, but you've definitely used it. Other than being one of the most ubiquitous programs on the planet, it's been the go-to word processing system for more than a quarter-century because it's as basic as it gets. But occasionally, you've got assignments that beg for a lot more options than simple […]
Almost everyone has their smartphone in a case of one kind or another. Beyond simple protection, finding a case that can charge your phone on its own, but doesn't feel like it's also adding a couple pounds to the phone's weight is the tricky part. Billed as the world's thinnest battery case, the ThinCharge iPhone […]
Impressionist lulz!
Actually Post-Impressionist lulz.
I'm waiting for the new release of "Drone Operator 2012" by EA games. Comes with a bar of soap for washing your hands and conscience clean after.
I'd get right to work tying up that copyright before the makers of Seal Team 6 do it.
[#Spoilers] "Ender's Game" did it first.
I just had to click on the "HUMOROUS SITUATIONS DEVELOPING FROM ITEMS BEING IN OR ON EARS " tag. Just to see what else there might be.
No, I won't spoil it for you.
Comments are closed.


text:
Does apple pucker mix good with mountain dew
kgb answers » Food & Drink » Does apple pucker mix good with mountain dew
Tag: mountain dew
Sunday, February 05 2012
Source: http://www.barnonedrinks.com/drinks/p/peckerhead-8330.html
Related questions
Top 10 questions Food & Drink
- how is the best way to reheat donuts?
- is slushie spelled slushie or slushy?
- How do i make a volleyball shooter
- The stomach lining of beef is a popular meat product called.?
- What is in a surimi roll?
- Whats a good substitute for pearl sugar?
- what do you call a mini champagne bottle?
- How do u make a grape tootsie pop shot
- How to make cupcake frosting
- Does Chic-fil-a have onion rings?


text:
Activity Feed
Register or sign in to start receiving activity updates from around Kongregate!
Complete Initialization for 10 kreds
Congratulations! You've completed your Kongregate account!
Keep exploring Kongregate with more badges and games!
Hide the progress bar forever?
Topic: Forum Games: Continuous Games /
Picture Wars (6)
Pirates own the sea.
Megatron has no barriers.
F***, not again. Sebba!
Jesse: "We killed your mother at the dead of night"
James: "And gave Lavendar Town a fright"
Meowth: "Meowth, that's right"
EDIT: Sebba, you f***ed up my move
Teenage Ginger Mantis controls your controller.
But these graphics are too good. (in other news, yay for MGS5)
Behold, the almighty destroyer of cards.
You can't intercept an invisible missile.
How dare you be different! I say NEIN!!!
Stop using references me Grimlock don't understand, makes me want to smash!
Oops, quite oversized, anyway, even more powers.
Just cause he has super strength, doesn't mean he has strength equal to Superman (but I'm not about to start a flame war, I'll just continue with the pictures)
Don't make me bring out the math, he is undefeatable. (except for the obvious weakness, don't put it down, don't, I know you're thinking of it, DON'T!)
Get more out of your Kongregate experience. Take advantage of ad-free gaming, cool profile skins, automatic beta access, and private chat with Kong Plus.
Learn more »
Did you know you can now score GameStop PowerUp Rewards® Points on Kongregate?
Find out how »


text:
Steve Maxwell, Canada's Handiest Man, demonstrates Eco Wood Treatment, a Canadian wood treatment product that works wonders on lumber.Continue Reading
VIDEO: Building Scale Architectural Models
In this video, Steve Maxwell, Canada's Handiest Man, explains the usefulness of scale architectural models before beginning a custom home build.Continue Reading
VIDEO: Septic System Revival How-To
Watch and see how Steve revived a hopelessly clogged septic system without replacing it. Faster, cheaper and less disruptive than the usual methods, as you'll see.Continue Reading
VIDEO: How to Make Perfectly Neat Caulking Joints
This simple, tool-free caulking technique will change the way you apply sealants forever – get professional results, even if you've never applied caulking before. Watch until the end of this video to see how it's done.Continue Reading


text:
Engine:401 Nailhead
Vehicle Title:Clear
Fuel Type:Gasoline
Exterior Color: Red
Make: Buick
Interior Color: White
Model: Skylark
Number of Cylinders: 8
Trim: Gran Sport
Drive Type: Automatic
Options: Convertible
Mileage: 28,508
Spokane, Washington, United States
I have a 1966 Buick GS Convertible. It has a running 401 nailhead with automatic trans. It runs and drives strong I am currently replacing the starter. It is equipped with power steering, power brakes, tilt , bucket seats, console. All glass is good. Solid car with only surface rust in trunk. Has original rally wheels including the spare. Has a few dents and dings great solid restoration project or daily driver. Needs new convertible top and top motor. If you have any questions call Mike at 509-768-6890
It's nighttime in China, and Buick has just concluded an evening event the day before the first - and only - press day of the Shanghai Motor Show. The star of this evening's party was the Buick Riviera concept vehicle, a plug-in electric hybrid coupe that the automaker says gives a glimpse at its future design direction, not to mention resurrecting some nomenclature from the brand's history that includes a similarly named concept from 2007.
The shape of the Riviera is said to be inspired by water. While the traditional Buick "waterfall" grille is present, the front end gains a more aggressive note thanks to what appear to be vertical air inlets below each headlight.
As for the concept's drivetrain, Buick says it uses General Motors' new dual-mode wireless plug-in hybrid electric vehicle propulsion system, or W-PHEV for short. The keyword there is 'wireless,' as the Riviera can charge its onboard battery packs with a traditional cable or wirelessly via a "sensory recharge panel" underneath the car.
A Nice, New Buick Aims For Middle Of The Road
Any time someone describes some portion of a car or a driving experience as being "nice," I want to either A) throttle them or B) run as fast and as far as I can from that vehicle. "Nice" is among the most insidious words in the English language - at best it's vague, and at worst, it conveys the exact opposite of its literal meaning. Yet it seems to be used with damnable frequency when it comes to verbally illustrating vehicles. "It looks really nice," or "These seats feel nice," or, heaven forefend, "It's got a nice ride," are all windy signifiers of absolutely nothing resembling a concrete opinion. "Nice" is the adjectival equivalent of meekly smiling and nodding your head.
Of course, I'm as guilty as the next person of having thrown English's least powerful descriptor around. There's even a chance that, rant aside, you'll catch me making nice in reviews to come. That's fine, but you should know that when you stumble upon such usage, past or future, that you've found a sentence in which I'm simply applying a bare minimum of effort to the task.
City, Slicker
We admit it. We have no earthly idea how this whole thing is going to shake out.
Typically, after driving a new car or truck, we come away prepared to hazard a guess as to whether said model has a good chance of being a sales success. We've amassed enough time watching the industry, scrutinizing the competitors, and so on, to make a reasonably educated bet. Yet here we are, days removed from driving the new 2013 Buick Encore, and we still have no bloody idea.
2040Cars.com © 2012-2016. All Rights Reserved.
Designated trademarks and brands are the property of their respective owners.
Use of this Web site constitutes acceptance of the 2040Cars User Agreement and Privacy Policy.


text:
Hello, and welcome to The Deepweb Master's "deep web" link list! Here I will list a few well-known "deep web" websites, as well as a few handfuls of lesser-known sites.
- Thu, 05 May 2016 17:53:00 GMT
Read More about fqniz5flbpwx3qmb onion Hello and welcome to Pastebin
Pastebin PRO Accounts SPRING SPECIAL! For a limited time only get 40% discount on a LIFETIME PRO account! Offer Ends Soon!
- Thu, 05 May 2016 07:01:00 GMT
Read More about DOVE SCARICARE PEDOPORNO FOTO VIDEO SEXY CHILDREN


text:
They will be serving ham and beans, cornbread, fried potatoes, desserts and a choice of coffee, tea or lemonade.
Cost is $9 for adults and $5 for children.
The Lady Volunteers are also planning a Craft Fair for Saturday, Nov. 17.
The cost to set up is $15 if you use one of the center's tables, or $10 if you provide your own table.
To reserve a spot or get more information, call Anita Ave at 448-3023.
Staunton First Christian Church News
Sunday school begins at 9:30 a.m., with worship service following at 10:30.
Doug Parkey is the minister.
Children's Church and Wee Worship meet at 10:30 a.m., in the Educational Building.
If you need transportation to morning worship service, please phone the church office at 446-3211.
Sunday evening service begins at 6 p.m.
Wednesday evening Bible Study and Prayer Group meet at 7 p.m.
The Pastor Appreciation Dinner will be Oct. 21, at the Staunton Community Center.
Trunk or Treat will be at the church, Oct. 28.
Staunton United Methodist Church News
Sunday worship service begins at approximately 10:45 a.m.
Our pastor is Scott Aselage.
Remember the Community Food Pantry is open in the church basement from 3-5 p.m., on the last Wednesday afternoon of each month.
The next food pantry day will be Wednesday, Oct. 31.
Anyone in the Staunton area in need of help is welcome.
We appreciate the support of all the churches, schools, civic organizations and individuals who help make this needed outreach a success.
Please keep praying for everyone who is battling illness, as well as all the brave men and women of our military and their families.
Also remember in prayer all the folks in nursing homes and hospitals and those who have lost loved ones.
Go out of your way to be kind to someone and pray for everyone.
If you have news to share, you can call 448-1591, or send the news items to 4954 W. Happy Holler Rd., Brazil.
All news is greatly appreciated.


text:
I have sold a property at 2111 11 Mahogany RO SE in Calgary.
No waiting for anything to be built here. Located at the entrance of Mahogany with quick access to Stoney Trail, 52nd St and Deerfoot Trail, this 1 bedroom and den home is ready for a new owner! This condo is on the main floor and only blocks away from the dog park making it perfect for those who have small pets (weight restrictions are in place). This home has a functional layout with granite countertops, cork floors, and stainless steel appliances. Both bedroom and den have large closets and the master has an upgraded fan light. The balcony faces south and gets lots of sun to enjoy all summer long or head to the beach 2 blocks away! Mahogany is a beautiful growing community with multiple lakes, beach club, and the shopping centre beside Oak51 will soon be opening. This home is perfect for an investor or as a starter property. With quick possession possible make sure to book a showing before it is gone!


text:
A project of People For the American Way dedicated to monitoring and exposing the activities of the right-wing movement. Learn More >
Barber: If DOMA Is Struck Down, 'it Will Be the Criminalization of Christianity'
Last week, Liberty Counsel's Matt Barber appeared on Steave Deace's radio program last week to discuss the Supreme Court hearings on Proposition 8 and the Defense of Marriage Act where he made the dire prediction that if DOMA is struck down, it will lead to wholesale persecution of Christians.
Citing the case of Bob Jones University v. United States in which the Supreme Court ruled that the IRS could revoke the school's tax-exempt status because of its racist policies, Barber predicated that if DOMA is struck down, "we automatically become the modern day racists" and that the nation would see "the criminalization of Christianity":
As soon as DOMA is overturned, the floodgates open. All of those [state] constitutional amendments are wiped out and schools like Liberty University, for instance, and private organizations with Christian ownership, we know the homosexual activists already have their gay married people planning to come and apply to Christian universities so that they will have a court challenge. The persecution is going to run rampant if gay marriage becomes the law of the land; there is just no questioning and that is a big part of the motive behind it.
If the federal government puts its official stamp of approval on homosexual behavior and says that it's equal to, in every way, natural heterosexual behavior up to and including marriage, then that officially pits the federal government against those who hold a Judeo-Christian worldview relative to sexual morality. We automatically become the modern day racists.
It's like the Bob Jones decision that said - which was a ultimately good decision - that said Bob Jones University could not have a ban on interracial dating. Well, they are going to apply that same type of logic to this. Basically, all bets are off; it will be the criminalization of Christianity.
It's the government against Christians if gay marriage becomes the law of the land and that's not hyperbole.
Filed Under
Organizations:Liberty Counsel
People:Matt Barber , Steve Deace
Related Items
Trending Topics
RWW Social Media
Most Popular
Chuck Norris Gets Behind The Chemtrails Conspiracy Theory
4/25/16 @ 12:05pm
Anti-LGBT Activists 'Testing' Target By Sending Men Into Women's Rooms
5/2/16 @ 10:53am
Utah GOPer Says Access To Pornography Violates His 'Right To Not View It'
4/21/16 @ 3:05pm
Pat Boone: The Government Should Outlaw Blasphemy And Punish Saturday Night Live If It Blasphemes Again
4/22/16 @ 2:05pm
Oath Keepers Website Warns Clinton Victory Could Lead To 'Outright Civil War'
4/21/16 @ 1:25pm


text:
United States
Find a Business Near: Harveysburg, OH
Harveysburg Population: 598Total Males: 323
Total Females: 275
Median Household Income: $ 53,304
Total Households: 239
Full U.S. census data is available here.
Business Industries in Harveysburg
Below is a list of the types of businesses in the City of Harveysburg for which we have Yellow Pages business listings. If you do not see your industry within the list below, adding your business will automatically create it.
- Auto Radio & Stereo Systems
- Boat Dealers
- Boat Equipment & Supplies
- Building Contractors
- Churches
- Churches & Religious Organizations
- Construction Companies
- Fire Departments
- Fruits & Vegetables
- General Contractors
- Grocers & Supermarkets
- Health Services
- High Schools
- Home Builders
- Marinas
- Police Departments
- Public Schools
- Remodeling & Repairing Contractors
- Road Side Services
- Schools - All
- Special Academic Education
- Stereos
- Towing
Don't see your category here? Adding your business in Harveysburg will create it!
Recent News from the Green Blog
Governor Cuomo Announces First Solar Schools Project At The New York Institute For Special Education In The Bronx
Governor Cuomo's K-Solar Program Increases Use of Renewable Energy in Schools (New York, NY) Governor Andrew M. Cuomo today announced the New York Institute for Special Education in the Bronx will be the site of the state's first solar schools project and will have solar panel arrays installed thanks to a power purchase agreement with SolarCity. This public-private partnership is..


text:
Tags Matching:
Bastille Day
Originally published 07/19/2013
Robert Zaretsky: Why the French Love a Parade
Robert Zaretsky is a professor of French history at the University of Houston Honors College, in Texas....[Bastille Day] was the Age of Reason's Woodstock — even with the presence of the National Guard, the citizen militia born in the creative chaos of 1789. Sporting their blue, white and red cockades, Guard detachments from across France came to affirm their region's attachment to the Revolution. For the French nation in 1790, the Guard was no less the authentic representative of the popular will than, say, Jimi Hendrix (wearing red, white and blue) riffing on the Star-Spangled Banner was the authentic expression of Woodstock Nation.While the Guard's role in the festival partly explains the military's presence in today's parade, there's another source. With the advent of Napoleonic and Restoration France, July 14 became the date whose historical significance dared not be spoken. It was the fledging Third Republic, born in the rubble of defeat left by the Franco-Prussian War, which resurrected the parade in 1880.
- More Doubts, Opposition To Sale Of Unique, Hartford Collection Of Political History
- How the Curse of Sykes-Picot Still Haunts the Middle East
- Kennewick Man Will Return Home to Native American Tribes
- Now it's the University of Louisville's turn to remove a Confederate statue
- A fortress built by Alexander the Great after he conquered Jerusalem has been discovered
- Liz Covart amazingly popular podcast helps her audience understand early American history
- Justus Rosenberg is still teaching at age 95
- Glenda Gilmore chides Yale for deciding to keep the name of Calhoun
- The historian and cartographer Bill Rankin has developed a new way to visualize slavery
- Paula S. Fass says young Americans need required national service


text:
We gaze up in equal parts wonder and fear at the giant sphere that has appeared above our city. It contains the dead husks of our aspirations in the form of hilarious nostalgia. Awk-waaaaard!
His eyes black. His body in repose. Staring at an infinite horizon forever. Never dying or even aging.
Remember bees? They are not dying out, their queens had led them to the safety of the sphere. They will be preserved through the coming tumult.
This is your typical consumer model throne. If you just want a cheap prop, it's fine. If you want to actually sit like a king, pony up the cash and get yourself a prosumer model. This entry level stuff is more for a duke or baron at best.
Do you wish to know what computers will be doing in the year to come? With a sigh I shall exert the minimal effort it takes to reveal all. Feel free to print out these predictions and share them with your friends via fax.
Chess only has 64 places to stand. BDO has full 3D movement. There's no comparison!
goku hears a wolf howl and joins in for three straight episodes
Airbrush those disgusting wrinkles. Return their flesh to childlike purity.
The Something Awful front page news tackles anything both off and on the Internet. Mostly "on" though, as we're all incredible nerds.
Copyright ©2016 Rich "Lowtax" Kyanka & Something Awful LLC.


text:
Most important to this update, however, is that Venetica is just very pretty. Take a look at the gallery below, and since we live in a somewhat ADD-based society, if you look at nothing else, look at the first and fifth pages of screens to see why I'm enamored with the visuals.
Venetica is scheduled to be released on both the Xbox 360 and PC this October.
Final Fantasy IX PC May 8 • 9:00am PDT/12:00pm EDT
Grim Fandango Remastered May 15 • 9:00am PDT/12:00pm EDT
Persona 4 Golden Continues! Every Monday • 5:00pm PDT/8:00pm EDT
Grandia II Continues! Every Wednesday • 2:00pm PDT/5:00pm EDT


text:
Dance Spot
11:00 AM Sun, Apr 27, 2014
Venue: deCordova Sculpture Park and Museum
51 Sandy Pond Road, Lincoln, Ma 01773, Lincoln, MA 01773Contact:
Deborah Belanger
0 people saved this
Join multimedia artist Elisa H. Hamilton as she gets her groove on in the Sculpture Park! Hamilton's Dance Spot is a participatory art experience that will transform areas of the Sculpture Park into outdoor dance floors. Each Dance Spot (a colorful diagram illustrating a site-specific dance routine) will be paired with a song selected by the artist and related to the nearby art and landscape.
Free Admission to 9 Trustees Houses
The Trustees of Reservations Kick Off 125th Anniversary During National Preservation Month With Free Statewide...
Search All Listings Here.


text:
Video: Kilian Fischhuber in Rocklandsby Björn Pohl - UKC Jul/2011
This news story has been read 5,159 times
Here's a video from when Kilian Fischhuber, Anna Stöhr, Emanuel Moosburger and Co. visited Rocklands last summer.
There are some short clips the guys climbing on various problems including Kilian's 2 x dyno FA Air star, ~8B, which I think is still unrepeated. And then there's Kilian doing the classic Rhino and the four-mover Sky, 8B+, another 2 x dyno problem.
For those of you interested in what he's talking about, he is basically saying Rocklands is one of the very best bouldering areas in the world, and then how cool the boulders are, and than about how he did Sky
All in all a pretty nice video for you to enjoy.
Kilian Fischhuber has many sponsors, including: La Sportiva, Vaude, Edelrid and Sport.Land
Britain's Shauna Coxsey managed to secure a second win in a row at the IFSC Boulder World Cup in Kazo, Japan at the weekend, just... Read more
Said Belhaj has repeated Chris Sharma's Paoichulo, 9a+, at Oliana, in Catalunya. This was the Swedish climbers hardest route to... Read more
James McHaffie has added a new E9 6c - House of Talons - to Dinas Cromlech in the Llanberis Pass. The fact that a... Read more
Two months ago, Jimmy Webb made the first, and so far only, repeat of Nalle Hukkataival's Livin' large in the... Read more
A couple of months ago, Andy Gullsten became the first to flash King of limbs, ~8B/+, at Roadside in Rocklands, South... Read more
Late in the season, when temperature and humidity perhaps shouldn't really allow it, Dave Graham has made the second... Read more


text:
SmartScore 99
SmartScore 99
SmartScore 86
SmartScore 92
Here's the question you clicked on:
Is taking the derivative of e^x technically using the exponential rule?
derivative of e^x is e^x, it doesnt change not power rule if thats what you mean
I know what the derivative of e^x is, that's not what I asked.
theres no such thing as an exponetial rule btw
@jayz657 http://en.wikipedia.org/wiki/Differentiation_rules#Derivatives_of_exponential_and_logarithmic_functions
that link shows derivatives of exponential functions there is no rule for it, all you need to know about derivatives of e^x is e^x or if your talk about functions like 2^x then you need to log the function so you could bring down the x and take derivative of it
would you agree that \[d/dx(2^x) = 2^xln(2)\]
yea doing derivatives of y= 2^x is different from e^x since you dont need to do logs for e^x ln(y) = xln(2) 1/y dy/dx = ln(2) dy/dx = yln(2) y' = 2^x ln(2)
Yes, this is just a specific case for the exponential rule: \(\large \frac{d}{dx}(e^x) = e^x \ln e = e^x * 1 = e^x \)
Thank you @AccessDenied
You're welcome. :)


text:
Writing and Communications Associate
Endeavor 9 reviews - New York, NY
This job posting is no longer available on Omidyar Networks. Find similar jobs:Writing Communication Associate jobs - Endeavor jobs
About this company
Endeavor breaks down barriers that prevent emerging-market entrepreneurs from reaching their high-impact potential. Hailed by NYT columnist...


text:
Christoph Waltz, Tilda Swinton in Terry Gilliam's "Zero Theorem" clip
March 5, 2014 - 15:46 AMT
PanARMENIAN.Net - A new clip from Terry Gilliam's The Zero Theorem has been released, Digital Spy said.
Unveiled exclusively through Digital Spy, the preview sees Christoph Waltz's character Qohen Leth chatting with a computerised therapist named Dr Shrink Rom - played by Tilda Swinton.
Computer genius Qohen struggles to name things that bring him joy, while Swinton's character pushes him to elaborate on his feelings.
The movie centres around Qohen as he is hired to discover the meaning of existence (or lack thereof), but his work becomes more confused when he falls in love.
David Thewlis, Matt Damon, Mélanie Thierry and Ben Whishaw are also among the supporting cast.
The movie is Gilliam's first since 2009 fantasy The Imaginarium of Doctor Parnassus.
Top stories
With an estimated $1 billion in annual sales, Gagosian works across various eras, represents living artists like John Currin and Mark Grotjahn.
This will be an exceptional and rare opportunity to showcase the Republic of Armenia and Armenian arts in the United States.
Nazarian will present "I Hate Dogs" by Suzanne Khardalian, a film about one of the last Genocide survivors residing in France.
Denis Shulgin (violin), Lev Iomdin (violin), Georgy Tsay (violin) and Yevgeny Stembolsky (violin), Alexandra Stychkina (piano) will perform.
Partner news
Latest news
Armenian American Museum to host exhibition on Latino Americans The event will screen footage from the PBS documentary series "Latino Americans" and feature an engaging discussion with Jorge N. Leal.
Yerevan exhibition displays paintings by children with autism During 2007-2016, VivaCell-MTS has allocated AMD 151 million to a center that provides intensive treatment to children with autism.
"Tulip Fever" trailer features Alicia Vikander, Christoph Waltz (video) Set in 17th century Amsterdam, the period drama follows a young artist who becomes romantically involved with a married noblewoman.
Armenian-Americans seek $15 mln aid for Syrian refugees in Armenia "We remain deeply concerned about the ongoing unrest and violence in Syria, and its impact on minority populations," the AAA said.


text:
Good PR for the Cactus Club. I now know about it and may visit and give them some business for showing respect for the bikelane. The Cactus Club Cafe opened up on Adelaide Street West in Toronto's … [Read more...]
OH YEAH! Cactus Club stops valet parking in bike lane after tweets
BOO! Top 20 Halloween Costumes for Cyclists
Halloween is upon us once more. Pumpkins are being carved, fake cobwebs are being strung, and for cyclists all over the country bikes are being transformed into vehicles of pure … [Read more...]
The top 5 fall bike rides in Toronto
Fall bike rides in Toronto are a great activity through mid-November until the temperature drop. Mountain bikers in particular have it made in autumn, when trails become surrounded by blazing … [Read more...]
BIKELOVE: Kiss your ride, not the bride, at Nuit Blanche
How much do you love your bike? Many marriages end with some version of "you may kiss the bride." But for one night, people in downtown Toronto were asked to kiss their ride … [Read more...]
OH YEAH! 12 Reasons Why Biking is Better Than Tinder
There's a lube joke here somewhere... There are so many reasons to love biking. It's a fast, enjoyable way to get to exactly where you want to be (location-wise), and who doesn't love the … [Read more...]
OH YEAH: Richmond and Adelaide Cycle Track extensions are going in!
Work is progressing on extending the Richmond and Adelaide Cycle Tracks east to Parliament! Wonderful pics from the City of Toronto Cycling Facebook Group. Buffer markings for the Richmond Cycle … [Read more...]
OH YEAH! Pop-up bike lane on Bloor St to be unveiled at Open Streets TO
This Sunday!!! Event Date: Sunday, September 6, 2015 - 09:00 to 13:00 Event Location: Open Street TO Markham & Bloor See map: Google Maps We're unveilling a pop-up bike lane on Bloor … [Read more...]
TECH: Gadgets for cyclists provide directions, theft protection
Honestly a pretty decent lengthy article about a lot of new bike tech products. Ever wish your bike could give you directions while you ride, turn on a motor to give you a boost up steep hills, or … [Read more...]
OH YEAH! Cycle tracks to be extended along Richmond-Adelaide corridor
Well, this is light speed for Toronto. After deciding in early July to extend the pilot Cycle Tracks on Richmond and Adelaide over to Parliament St, work is ready to start on actually doing it! If … [Read more...]
OH YEAH! Librarian Bikes Around San Francisco Towing a Mini Library
School librarian Alicia Tapia is on a mission to spread the love of reading. Knowing the important influence books can have on literacy and learning she started towing a miniature library around San … [Read more...]


text:
PROMOTION from the Seniors Inter-County Leagues Division 3 remains on the cards for Oxfordshire Ladies Over 50s following a slender win over Devon at Torquay.
Both Oxfordshire pairs beat the Devon No 1s, but lost championship tie-breaks to the second couple.
The crucial contest saw Ana Coggon and Liz Gilkes win in straight sets as Oxon edged the tie 6-5 on sets, with the rubbers even.
It means a victory in the final match against Berkshire will move Oxfordshire into Division 2.
Latest Sport news
- Oxford United to host drinks and barbecue before crunch Wycombe clash
- Oxford United fans' chat
- Chris Maguire hails 'remarkable' away support as Oxford United beat Carlisle
- Oxford United keeper Benji Buchel so thankful to Danny Hylton for goalline clearance
- Missed chances frustrate Oxford United head coach Michael Appleton in victory over Carlisle United
- FOOTBALL: Banbury United celebrate return to top flight after play-off victory
- WEEKEND RESULTS: April 30-May 1
- FOOTBALL: Oxford City sign off with home defeat
- CRICKET: Oxfordshire start Unicorns Counties Trophy bid with defeat to Devon
- VIDEO: Highlights from Oxford United's win at Carlisle United


text:
The tulips are nearly upon us… aren't they? Search marketers are a little like tulips: perennially colorful, and it takes a lot of them to screw in a lightbulb! Arghh, sorry. Writer's strike and I foolishly outsourced the joke writing. Let's get serious… it's cheaper.
Prospective Toronto speakers, the SES Toronto show is not that far off (June 17-18, 2008) and program planning is well underway. From now until March 31, 2008, we'll be taking new session ideas, as well as proposals for the returning sessions (listed at the very end of the full post… read on).
Related reading
11 extraordinary uses of Augmented Reality (AR)
Jess Butcher, the director and co-founder of augmented reality app Blippar, is speaking at our Shift London event in May, so to prepare for this occasion, we thought we'd get fully immersed in the world of AR.
Beyond local SEO: Greg Gifford on how to win the visibility race
Last Friday at a packed-out Brighton SEO conference, expert local search consultant Greg Gifford delivered a fast and furious presentation on the secrets ... read more
Shift London: Are you ready to join the #Digirevolution?
What makes a digital influencer? Is it follower numbers? The ability to find and create great content? Or just a genuine passion for transformation and digital change?
Seth Godin: Nobody makes a purple cow by sticking with what's safe
Yesterday's over. Being different is what's going to help you win tomorrow – not simply repeating your previous success. A century ago, ... read more


text:
Click here to post it!
Baby Snuggie's
Hope for finding Everett Little
Croak Skull Illusion Scarf
I love to knit hats for friends and...
Ribbon Top
This didn't look nearly as gaudy as...
Crochet Market Bag
'Like Water for Chocolate'....by The...
Pumkin Trivets w/Fleece
Hooded Baby Blanket
Olivia's Shrug
Lacy Stole 70337AD
Pupa' mouse toy
Popcorn stitch afgchan
Baby Sweater
This was my second project ever. I love...
Hat/ Scarf
Beret & Cowl
Lion's Laguna Beach washcloth pattern
Display Order: Newest First
Surprise Me!


text:
East Valley Animal Hospital
81 W Guadalupe Rd
Gilbert, AZ 85233
(480) 892-1577
Mon - Fri: 7:30AM - 5:30PM
Sat: 8:00AM - 1:00PM
Sun: Closed
- Anesthesia
- Canine and Feline Practice
- Critical Care
- Dentistry
- Dermatology
- Emergency Medicine
- Internal Medicine
- Nutrition
- Ophthalmology
- Pathology
- Radiology
- Surgery
- English
- Any
- American Express
- Care Credit
- Cash
- Discover
- Mastercard
- Visa
Alan Mafara
5 stars Larry S Featured review
We have been going to this vet for several years. They are thorough will all four of our dogs. They show compassion and true concern for our dogs. Highly recommend this office to others.
Thank you very much for taking the time to give us your feedback, we appreciate it!
5 stars Jen G Customer since 2013
Love all of the staff! They are kind and compassionate and give you confidence that your little fuzzballs will get the best of treatment!
Thank you for taking the time to leave your feed back, we appreciate you and your fuzzballs.
5 stars Teal P Customer since 2011
Great doctors and staff.
Thank you!
5 stars Rick D Customer since 2012
I have always been happy with people and services provided at the East Valley Animal Hospital. I have even mentioned and recommended you to my friends and family should they need the services of a vet.
Thank you so much!
5 stars Patrick F Customer since 2012
The neutering procoess was fantastic. Clear communication about scheduling and revquirements for pre and post op care. A call to check after procedure. we had to get a larger cone the next day and make sure his bowels and bladder were okay. The staff were extremely accommodating by taking him in immeditatelyas they were attending other patients. Would recommoend this location and Dr. Mafara highly.
Thank you for taking the time to leave your kind words. Bisbee was a great patient and look forward to seeing you all again!
5 stars Stefanie M Customer since 2011
The staff at EVAH are always amazing and really take the time to make sure your questions are all answered. I wouldn't go anywhere else!
Thank you very much for your kind words, we appreciate you and yours.
5 stars Juana R Customer since 2007
Even though we had to make the hardest decision with Azzie, putting her down was the best choice for her. She was suffering too much. The doctor and technicians were extremely kind and helpful with our beautiful 10 year old Australian Shepherd. We know that Azzie is in heaven enjoying herself!!
Our heart goes out to you and your family, we are glad we could be here for you and yours. Thank you.
5 stars David F Customer since 2001
Everyone is always very friendly and helpful
Thank you for your kind words, we appreciate them.
5 stars Judy B Customer since 2002
Very pleased with all of the staff!
Thank you for your review.
5 stars Cindy E Customer since 2015
They are very friendly, caring, attentive and take the time you need patiently.
Thank you! We appreciate you!
5 stars Vicki D Customer since 2010
Dr. Mafara is amazing. Does everything that needs to be done to get your fur baby healthy. I look forward to many more years of him taking care of all my babies.
Thank you for taking the time to let us know. We do appreciate you and your fur babies.
Also in Gilbert
Physical Medicine
Gilbert Physical Medicine
Pediatric Dentistry
Kidiatric Dental
Heating and Air
Ken Muncy Air Conditioning, Inc.
Alpha Dentistry
Medical Clinic
Gilbert Center For Family Medicine
A Plus Chiropractic Care
AAMCO Transmissions & Total Car Care
APR-Automotive Performance & Repair