kamenges
Member
Originally posted by ganutenator:
What does happen when you overload a stepper motor?
The rotor and stator magnetic poles move into and out of alignment. This results in the rotor being pulled along with the stator magnetic field and then as the stator field progressively pulls ahead of the rotor, being pushed forward as the like stator magentic pole comes up behind it, and then gets pushed backward as the like pole pases the rotor pole and the complementary pole comes up from behind (how's THAT for a run-on sentence). Rinse and repeat at the pole frequency difference rate. Basically, the motor tries to shake itself to death.
Originally posted by ganutenator:
When I remove the run signal from the drive, it doesn't stop (w/ parameter F441 at 250%) the drive. I have to power down the drive to get it to stop. Customer is worried about that too.
The drive is probably set to ramp stop. Since the rotor is shaking around so violently the drive never sees the rotor as stopped. It stays enabled trying to get it to stop, all the while being the reason it can't stop.
Have you attempted to run the motor disconnected from the load at the higher torque limits to see if it will run smoothly that way? In any event, the cost of a feedback device is starting to look pretty attractive compared to the cost of your time. Feedback will keep the stator magnetic poles in the proper alignment to the rotor magnetic poles. This can go a long way toward getting the motor to behave.
Keith