Multiple power supply for arduino controlled dc motor I’m working on a project where I want to control a motorized fader with an arduino.  I have a dual H-Bridge board to control the motor, but the thing is that it is a 10V motor.  I’m thinking of using a secondary power supply on the H-Bridge to power the motor with a proper voltage.
So here is where my lack of electrical knowledge comes into play.  My H-Bridge has the following connections: a set of +/- poles to provide the power to the motors, 4 motor control pins (2 per motor to control their direction) and 4 motor power pins (2 per motor).

If I was using the Arduino as the power source for the DC motor, I would connect the +5v rail to the + terminal ot the H-Bridge and the Gnd rail to the - terminal, which would, in turn act as the ground return for the control pins.

If I am to use an external power supply, how do I wire it properly so I don’t blowup the arduino or the h-bridge?  I’m guessing that my secondary power supply will be connected to the +/- poles of the H-Bridge and the the - pole will also get connected to the Gnd rail of the arduino?

Is that correct?
According to the datasheet on the L298 IC the connections you described should be right. First I would recommend to connect 10v to the + and - rails and measure the voltage on the logical inputs if it is 0 or lower than 3v than that should be ok to connect an arduino. Also now you can connect an additional 5v power supply with an the -5v connected to the - rail on the board and try to connect the +5v volts to the inputs and measure the voltages on the output (or connect an motor) if everything is ok you can try to connect your Arduino.