VFD Output Filter?

[TwoBlocked]

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Motor rating plates explained- https://wiki.testguy.net/t/motor-nameplate-and-ratings-explained/66

Thanks, doesn't include the voltage rating of the winding insulation.

Depends on a LOT of factors., it's all over the map. Some manufacturers publish that data, others ignore it and leave it to the end user to find out on their own.

Here is a document from Rockwell that shows THEIR tested distances from Drive to Motor for each different VFD line they sell (or sold). If you pick out a single size, let's say 10HP 480V with 1200V winding insulation (non-inverter duty), you get the following from their tables:

PowerFlex 523... with nothing between the drive and motor, 40ft; add just a load reactor, 300ft; with a DV/DT filter, 1000ft.
PowerFlex 753... with nothing between the drive and motor, 40ft; add just a load reactor, 300ft; with a DV/DT filter, 1200ft.

But if you use minimum "NEMA MG-1 part 31 inverter rated" insulation of 1488V:
PF523... 300ft, 1000ft, 1000ft
PF753... 350ft, 1200ft and 1200ft

So note that the thing that makes the MOST difference is the motor insulation value. Once you step up to the 1488V insulation, the DV/DT filter makes no difference.

So Jraef's comment, although interesting, does not help when we are looking at the nameplate.

 

[ptonsparky]

Thanks, doesn't include the voltage rating of the winding insulation.

So Jraef's comment, although interesting, does not help when we are looking at the nameplate.

What do you still want to know?

 

[TwoBlocked]

What do you still want to know?

My latest question has been answered. Just letting everyone else know that the nameplate's insulation class does not indicate what the voltage rating of the winding insulation is.

 

[zbang]

Thanks, doesn't include the voltage rating of the winding insulation.

No, that's kind of the point, but other people may benefit from knowing how to read the info there.

 

[Jraef]

The only way to know the motor insulation voltage rating is to read the motor data sheet (if any) or ask the motor manufacturer. NEMA MG-1, Part 31 describes construction standards for motors intended to be run from inverters. Magnet wire that meets or exceeds the values required in that spec is more expensive than “average” magnet wire. So generally if a motor manufacturer went to the expense of using it, they will make that information clearly evident in their marketing of their motors. The safe bet then is that if you see NO MENTION of a motor being suitable for running from an inverter, it is not.