Hello! Been on and off the forums for a while. I built my MPCNC about 2 years ago, and I had the electronics mounted on the side. Well, about a week after finishing the build a windstorm blew through and the back door (which the CNC was next to until I got it moved to the shop) slammed into the BTT board and destroyed it. I recently got the jackpot from Ryan and an about ready to both move the table AND require/replace the electronics. But before I do, I got to thinking: are the stepper motors any good?
The Steppers have not been in DIRECT contact with rain/moisture, but they have been on my porch covered in a tarp and might have gotten the occasional misting/ humidity induced wetness. also, they have not had any protection from the cold (sadly they wont ever, because my workshop is not heated or insulated (its an old horse barn with a tarp to keep the rain out)). is there any way to test them to make sure they are good before hooking them up and spending hours troubleshooting to see if issues are board related or stepper/wiring related?
I’d disconnect the steppers, drop a little light oil into the bearings at each end, and rotate the shafts by hand. If they move freely then wire them up and see how it goes.
Use a paperclip or something to short the wire coils. The stepper should become much more difficult to turn by hand. If it does so with both coils, the stepper motor is probably fine. Since most stepper motors are wired A+, A-, B-, B+ shoring pins 1-2 and 3-4 should make the stepper more difficult to turn as opposed to leaving the wires alone. (This also functions as a test to see if the wiring is correct. I have bought steppers that were wired A+, B+, A-, B- before. It was a pain.)
They’re pretty useful to have around. It’s basically a little panel mounted controller with a couple of buttons, a control knob and an LCD that lets you run a stepper motor in a few basic ways like speed controlled forward/reverse, run at fixed speed when the button is held down, turn X rotations on button press, turn one way on button press and then turn unwind those turns on release, that kinda thing. It’s a good way to have a play with steppers for all sorts of stuff.
It is very rare for stepper motors to go bad. If it was working before, and you can spin the shafts, it is likely they still work. As for testing, in addition to the ZK-SMC02 mentioned by Jono you can:
If you are into Arduino, is it relatively easy to make a board/driver combo to drive the motors using A4988 or DRV8825 and any arduino board. There are pre-made stepper libraries as well as example code that directly energizes the coils in the correct order.
If two motors are wired together, one should spin the other like in this video. Growing up, my local electronics store had a pair wired like this, and I always had to spin them when I went for supplies.
Here is a way to drive stepper motors without a driver. The solution just uses a 12V power supply and a capacitor. You can use Dan’s suggestion instead of the LED to find the wire pairs for each coil. I’ve not tried it. I bumped into this video searching for the previous one.