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Signode
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Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/10/2015 7:34 AM

Dear Friends;

We have 11KW, 2pole, 400V inverter duty motor working at a take up conveyor of a single facer unit of a Corrugator machine. A separate cooling fan is with the motor. Normally motor works within 1700-2300rpm. For some reasons, we want to run the motor at 300-450rpm for some days. Kindly suggest if it is okay to run a 2pole motor at low speed? Normally motor current remains at 60%.

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Original_Macgyver
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#1

Re: Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/10/2015 9:25 AM

I don't see any real issues with the speed reduction but I do have a few questions:

  • What is the motor RPM on the data plate?
  • Is the motor overheating?
  • Is the inverter overheating?
  • Is this a common practice of using the motor VFD to switch from ~2000 RPM to ~ 325 RPM?

Good luck

Bryan

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JRaef
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#2

Re: Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/10/2015 1:31 PM

Well, it says in the title that it is 2 pole, then 400V which implies 50Hz, so the synchronous speed would be 3000RPM, slip speed probably around 2750.

With a separately cooled motor, I see no issue whatsoever. That's exactly what VFDs are for.

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Tornado
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#3
In reply to #2

Re: Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/10/2015 7:54 PM

And even more so, that is what the separate cooling fan is for.

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eltech
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#4

Re: Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/10/2015 11:10 PM

You may need to see you data sheets regarding torque for that motor, 300rpm about 5Hz may not be able to deliver the same torque at 50Hz.
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Tornado
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#5
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Re: Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/10/2015 11:26 PM

Good point; on a conveyor, full (or nearly full) torque will be needed even at low speed. Some motors and VFDs can do that, but not all.

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setlock77
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#6
In reply to #5

Re: Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/11/2015 8:47 AM

use a two speed transmission to slow down speed when needed.
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Tornado
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#7
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Re: Running A 11KW 2 Pole Inverter Duty Motor At Low Speed

08/11/2015 8:54 AM

Maybe, or maybe not.

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