8 wire stepper and drive overheating

I'm in the process of bringing a CNC mill I built ten years ago back to life. I had to disassemble and move the machine when I moved into a new house so much of the wiring had to be cut or unplugged.

It's taken me a while to re-learn all that I knew back in the days when I built and operated the machine but with patience I've got the X and Y axis moving after replacing both steppers, (they were overheating and running poorly) The X and Y were and continue to use 4 wire motors.

Now to the problem. The Z axis uses an eight wire stepper and it worked perfectly 10 years ago. Upon hooking it back up the way it was previously wired (I think?) it will fun for a very short time before I smell something burning and both the motor and the gecko 201 drive are getting very hot.

I've probed the motor with an ohm meter and have the wiring mapped out into 4 pairs with continuity of .6K ohms. I've tried a bunch of different combinations but It just gets hot quick along with the drive.

I happened to have another 8 wire stepper that I somehow mapped out years ago and if I hook it up it works perfectly and runs cool.


The machine, motors and drives all spent several years in a damp basement. Am I missing something with the wiring or perhaps the moisture has damaged the steppers?

Thanks all! Frustrating to have to re-learn all this stuff!

Hi,
I suspect you have one winding hooked up in reverse so that the parallel winding to it is forming a two winding transformer with the windings shorted.

Do you have a current clamp? If you do you need to clamp each wire in turn until you find the high current path, and that will in turn determine which pair
of wires you need to swap.

Craig

I've got a pretty fancy multi meter but that's about it.

I got it figured out. Once I removed the stepper motor from the machine to test it on the bench I could tell the motor was toast by the way turning the shaft felt. No cogging as one might expect. Replaced with another known good one and I'm good to go!

Thanks for your help all!