In my circuit my motor terminals are connected to the output of a VNH5019A motor driver https://www.pololu.com/product/1451. When the circuit is no longer powered I want to allow the user to freely rotate the motor (a dc motor) output shaft (which in my application has a load attached to it that I want the user to be able to move if power has disappeared). Currently if I rotate the motor fast in one direction and then suddenly change direction I can feel a "resistance" to the movement in the new direction. I assume this is because the motor is generating a voltage which opposes the movement in the new direction. Can anyone explain to me what is happening and suggest a modification to my circuit that would prevent this from happening?
The reason you are noticing it is worse at higher speeds will be because of the fly-wheel effect. The energy stored in the rotating core if proportional to the square of the angular velocity... So twice as fast = four times the energy.