Stepper motor slipping = damaged?
Stepper motor slipping = damaged?
(OP)
Hi folks,
I have a strange noobs problem that I can not wrap my head around. I have a plastic tubing stretcher that uses a stepper motor (Minebea 23KM-K709-07) to precisely do the stretching without going through any gearboxes etc.
It was working just fine for a long time, until one day, the motor slipped as we were experimenting on a new tougher plastic. Ever since, the motor has been slipping from time to time, even though we've not used the tough plastic ever since.
I thought that overloading a stepper motor once or twice shouldn't result in any permanent, adverse effect. Can anyone share their experience on how to best deal with this?
Thanks a lot!
I have a strange noobs problem that I can not wrap my head around. I have a plastic tubing stretcher that uses a stepper motor (Minebea 23KM-K709-07) to precisely do the stretching without going through any gearboxes etc.
It was working just fine for a long time, until one day, the motor slipped as we were experimenting on a new tougher plastic. Ever since, the motor has been slipping from time to time, even though we've not used the tough plastic ever since.
I thought that overloading a stepper motor once or twice shouldn't result in any permanent, adverse effect. Can anyone share their experience on how to best deal with this?
Thanks a lot!





RE: Stepper motor slipping = damaged?
You didn't by chance disassemble the stepper for inspection, did you?
That destroys their permanent magnets.
Mike Halloran
Pembroke Pines, FL, USA
RE: Stepper motor slipping = damaged?
Bill
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"Why not the best?"
Jimmy Carter
RE: Stepper motor slipping = damaged?
I really thought that the reason why the original design used steppers what that overloading them will not cause damage.
What can I do to verify the intergrity of the magnets?
RE: Stepper motor slipping = damaged?
Much lower? Say 20 percent lower. If same, no probs.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Stepper motor slipping = damaged?
Never noticed anything like that happening with them.
There remains the possibility that the stiffer tubing pulled something out of line, and the possibility that some lubrication point needs attention.
In particular, steppers often ship with only a preservative oil in their ball bearings. One (only) drop of sewing machine oil applied to the outside face of the bearing won't hurt. The bearings are almost always shielded but not sealed, so the oil will wick right in.
Mike Halloran
Pembroke Pines, FL, USA
RE: Stepper motor slipping = damaged?
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(2B)+(2B)' ?
RE: Stepper motor slipping = damaged?
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Stepper motor slipping = damaged?
More sophisticated drives, such as microstepping drives, use current feedback to achieve a fixed current magnitude in a rotating time sequence (sinusoidal or pseudo-sinusoidal) around the phases. This has even less chance of demagnetization, as the voltage is automatically adjusted to maintain the current level.
Unless you get into the "sensorless vector" style of stepper drives, the drive will not know that the load has increased, and will not try to dump in more current to overcome the load.
Curt Wilson
Delta Tau Data Systems
RE: Stepper motor slipping = damaged?
RE: Stepper motor slipping = damaged?
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: Stepper motor slipping = damaged?
Thanks for all the tips and ideas.
potteryshard: That's something I was reading up too. Is there a way to test that?
TurbineGen: No, the temperature is relatively constant and the motor is not contantly in use (> 10% duty rate).
I called the distributor last week - not only do they have no clue, but the motor has been discontinued without an equivalent! :-p
RE: Stepper motor slipping = damaged?
It isn't always easy to get an intermittent problem to cooperate however. It may not choose to act up while you are measuring outputs. It may be possible to temporary in a couple of low output lights matching the motor voltage parallel with the motor leads. When slipping an operator can glance at the lights to see if all outputs are firing.
RE: Stepper motor slipping = damaged?
I usually attach LEDs to the drivers in lab setups, but they don't add much information; when a driver isn't firing, the motor may twitch, but it doesn't rotate.
Mike Halloran
Pembroke Pines, FL, USA