I've been thinking about hybrid drivetrains. One thing that is bugging me is operation when one motor is off while the other is on. In a scenario in which the motors are connected with all the rotors on the same axis, I can easily see how the velocities would add up. But if one motor was turned off, wouldn't the motor just cause the other one to spin in reverse and not put out much power to the shaft (assuming there is a large load on the shaft)? The whole equal and opposite thing. If the load is much bigger than the drag of the motor running now backward, then all your effort would be going into spinning the off motor backward.
If the motors were hooked up in parallel through some gear and one was turned off, I can see how the power output would be decreased by at least half. The single motor that is on is losing power because of back EMF from the off motor.
Is the only way to overcome this is through some sort of clutch? Thanks!