@Nick_Parker Ok, so at the risk of exposing an area of ignorance, how does one go about shorting the coils? Incidentally, I’ve got the motor screwed down on the bed now and when the power drops, the bed sags a little but doesn’t drop all the way. The next step would be to find a way to ensure there is no movement so you wouldn’t have to re-home (downwards) if you wanted to continue a print for some reason.
@Tim_Rastall I’m thinking a 2x DPDT relays to the motor. one for each coil. The Commons would be from the motor coils, the NC would short each coil to a resistor, and the NO’s would be the normal route to pololus. This way, you;d energize the relay’s during normal Z-moves. If the power died, the relays would open, sending the motor coils to the resistor loads. this would burn heat as the Z bed dropped with gravity, slowing the descent.
@Tim_Rastall @Eric_Moy try putting jumpers across the pairs on your motor.
If they follow standard wiring, the pairs will be next to each other. (so the 1st and 2nd will be connected, and 3rd and 4th will be connected going from one side of the plug to the other.)
This actually makes it quite hard to move. I bet with your gear ratio it would stop it completely
and if you still don’t get what i’m saying, just take the wire from your motor and start connecting holes on it then trying to turn it, you’ll know when you hit a pair because it will be way stiffer.