Bridgeport Series 1 stepper motor issue.

More
20 Jan 2020 02:24 #155221 by PhilCNC
Alright so I got my machine up and running and it seams like one of my stepper motors has a problem. Basically I can't get my Z axis stepper to move like it should. I've isolated the issue down to just the motor itself, the drive, wiring, leadscrew etc are alright. So I don't really know how I should start testing this motor further to see what exactly is wrong, but I feel like the motor must have lost it's magnetism somehow. It has barely any torque, I can stop the motor with my hands. I tested the inductance, current, resistance, and verified the voltage was the same as the x and y axis , and all those tests point to this being a fine motor, so now I can't help but think that maybe the permanent magnets are what's to blame. I think I will take it to an electric motor repair shop Monday if they're open. Maybe I'm missing something. If anyone has any advice, I would appreciate it.

Please Log in or Create an account to join the conversation.

More
20 Jan 2020 02:34 #155223 by Leon82
Is it on the quill or the knee screw?

Some here have mentioned the knee can be problematic.

Have you tried switching it with another axis motor?

Please Log in or Create an account to join the conversation.

More
20 Jan 2020 02:50 - 20 Jan 2020 02:51 #155224 by PhilCNC
It's the motor on the quill. The knee is hand cranked on this machine. I tested the motor on and off the machine, at this point I don't think there is anything more to learn by switching it for another axis, I'm sure it would behave the same on the other axes. Anyway, I should find out if this motor is the permanent magnet, variable reluctance or hybrid type. Just to get an idea of the condition of the motor turned the shaft by hand and it seems like the z axis has less of the cogging effect when compared to the y axis. I don't think the coils are burn't. I think the permanent magnet has lost it's magnetism some time in the past. I'm not sure why the x and y axis are working fine though. Thanks for the reply.
Last edit: 20 Jan 2020 02:51 by PhilCNC.

Please Log in or Create an account to join the conversation.

More
26 Jan 2020 17:09 #155825 by andypugh
You could measure the AC voltage on a phase when turning the motor.
If that is less than with another motor that would definitely point to a demagnetisation problem. This can be caused by overheating (newer magnetic materials are a lot more temperature resistant)

Please Log in or Create an account to join the conversation.

More
26 Jan 2020 17:13 #155826 by bbsr_5a
the OHMIC of the Phase shoudt also be the SAME as other Identical Motors and quite less then 3Ohms
Nema24 see offen 1,2 OHM if it is around 5 it is for shure burned

Please Log in or Create an account to join the conversation.

More
26 Jan 2020 21:30 #155859 by tommylight

bbsr_5a wrote: Nema24 see offen 1,2 OHM if it is around 5 it is for shure burned

???????????????????????????
Please refrain from giving such wrong information to users!
There are plenty of stepper motors motors with more than 5 Ohm winding resistance, and you can not conclude it is burned just by the resistance, and if it is burned the resistance will go down , not up.
You can check if the resistance of all the coils is the same, and if any of them is a bit low, then it might be burned.
The following user(s) said Thank You: BeagleBrainz

Please Log in or Create an account to join the conversation.

More
23 Mar 2020 22:57 #161293 by PhilCNC
Hi so my CNC Mill is having issues, this video will explain it. I'd like to add that the it's not a problem with the power supply either, the problem persists even if the Z axis is the only one with power!

Please Log in or Create an account to join the conversation.

More
23 Mar 2020 23:17 #161299 by andypugh
Hmm, you already covered most of the things that I thought of during the demo.

It doesn't look like the machine has a heavy Z, but just out of interest, is the maximum speed it will do the same both up and down?

I guess it's a rotating nut on the Z? It might be worth checking the nut suspension bearings.

On a very cheap ballscrew that I had on my mill, with a rotating nut, the plastic plugs in the ball return paths spun out and caused the balls to jam up at higher speeds. But I would guess that your machine has the original BP parts there?

Please Log in or Create an account to join the conversation.

More
24 Mar 2020 02:07 #161305 by tommylight
I do not see that you did test using x axis drive to drive the z axis motor, so do that. And vice versa.

Please Log in or Create an account to join the conversation.

More
24 Mar 2020 02:26 #161306 by PhilCNC
Thanks Andy for the advice, I will look more into the ballscrew and nut. In response to tommylight, I tested it off camera.

Please Log in or Create an account to join the conversation.

Moderators: piasdom
Time to create page: 0.102 seconds
Powered by Kunena Forum