Is it safe to backfeed Tic controller?

I have a Tic 249 controlling a NMEA23 stepper motor - all works well. When I rotate the stepper motor by hand when the Tic is not powered, the stepper motor generates enough power for the Tic to power up (or at least some LEDs on the board light up). Is this safe for the Tic?


It generally isn’t good practice to power a system in unintentional ways like that, but if the backdriving isn’t excessive (try using a scope to check that the peak voltage doesn’t exceed the Tic T249 controller’s maximum operating voltage of 47V), then it is probably okay. However, if it is dumping too much power back into the system, then you might consider adding a way to disconnect the motor either electrically (motor wires) or mechanically when the system is off and you want to backdrive it.