Quote Originally Posted by Tom J View Post
Jazz what do you mean by clamp and lock up when EMF gets high?
The PSU can have protection circuitry which trips the PSU into fault mode if voltage or current rise above certain threshold. So if the back Emf from motors is high. ie: Like when changing direction at high speeds with heavy gantry the current can spike above this amount and cause trip.

The caps in toroidal supply absorb this back EMF so it's not problem.