Loop of a wire and right hand rule
When the loop is the figure shown below will be rotated in clockwise
  direction the the slip ring connected to the red segment of the loop
  will give us the positive voltage and the slip ring connected to the
  black segment of the loop will give us negative voltage according to
  the Flemings right hand rule.


With the loop in that position, the induced voltage is zero so NO, there is no voltage generated at this instant or position. Reason: the induced voltage relies on rate of change of flux and with the coil vertical the flux cutting the coil may be at a maximum but the rate of change of flux is zero: -



Improved picture source here.

So, using the picture above, (and considering the case from position 1 to position 3), the voltage increases to a positive peak due to the rate of change of flux (that the coil is cutting) increasing. 

Conductor DC is indicating the flow of current should the generator output be loaded. Due to Fleming's right hand rule conductor BA also has current flowing the same way hence the terminal voltage on the closer slip ring is positive.

If you reverse direction it is the same as swapping the magnet poles and the waveform will be inverted. Flemings right hand (generator) rule: -



Strictly speaking this rule applies to the current direction but given that the current direction is dictated by the polarity of the induced voltage, it matter little. What ever way you try and rotate your right hand, if you reverse either the direction of travel or the magnetic field, current reverses and, by inference, induced voltage polarity reverses.