Anyone a permanent magnet motor expert here?

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
 
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.




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

Thanks for your help and explanation.
It is running smooth as silk now.
The car wash environment would probably be too harsh for an encoder.
It looks like it will be enough torque.
The only reason to go w/ the ipm vs the previous asynchronous motor was because the asynchronous motor had a motor fan which would allow the motor shaft and fan bearing to rust out.
I believe it is safe to say, that I can not compare torch of the asynchronous motor to that of the ipm 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.




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

Great job on the explanations.
 
Hello friend.
I see that the Toshiba Drive is twice the capacity of the motor...hence, there is absolute need to match them correctly in every aspect...
My suggestion would be:
1). ... have U done the correct type of Autotune...? try disengaging the motor from the gearbox and repeat a rotational Autotune.
2). After a successful Autotune, be patient to run the motor without connecting it to the gearbox... and observe its performance...
3). ... because of your application's demand on stable Torque, go back and select a constant Torque curve... this will enable you smooth out the Torque profile of this motor.
4). You should also stretch out the Accel. and Decel. time to let say 15-20secs.
5). Run the motor once again, observing its behavior...
6). Connect the motor back to its gearbox and run it on load this time.
7). If there is need for certain minor adjustments, do them.

I hope these help...✌️
 

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