# PF753/Perske motor problem



## bclowman (Oct 2, 2014)

Drive: AB Powerflex 753
Motor: Perske KCS 72.24-2 D
Y/Delta 440-480 9.5/15hp 12.5/18.5Amps 3490/7090 

60/120 Hz.

This is the motor data entered into the drive parameters.
460V, 9.5HP 12.5A 3490 60Hz. 2 Pole
Motor control option is V/Hz


Motor will not run wired Delta. Goes into a HW overload as soon as you hit run with motor making a high pitch squealing sound. I can change to Y and motor will run fine. I have had a Drive rep. from Mc and Mc attempt to run the motor in Delta and after a full day of many parameter changes and multiple calls to Tech support didn't gain in inch. The flipside is I can connect a "dumb" drive to the motor with no data entered and it will run the motor fine. Any input would be much appreciated. 
On another note: I changed the Poles to 4, with the motor wired Delta and with the 753 it didn't go into HW overload and started but did not sound right at all.


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## micromind (Aug 11, 2007)

Is the motor 6 leads? If so, what are they labeled? And what connections are you using for ∆? Have you checked for proper labeling of the leads?

In other words, need a bit more info.....lol.


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## bclowman (Oct 2, 2014)

micromind said:


> Is the motor 6 leads? If so, what are they labeled? And what connections are you using for ∆? Have you checked for proper labeling of the leads?
> 
> In other words, need a bit more info.....lol.


 

Motor is 6 lead. Leads aren't the problem as the motor will run fine with other drives in Y or Delta. 

Have 12 of these motors running on KEB's. Ran motor today on a cheaper Lenze with no problems at all. Tried a second 753 and it does the exact same thing as the other. 525 also and it acted the same as the 753. 



Another bit of info: on the 753 the start up current is 80 amps..... not inrush. 

The curve ball to me is why is it somewhat attempting to run set as a four pole. ( as if it's a type of 2 speed single winding motor???) yet other drives it doesn't seem to matter at all. 

Been doing this for quiet a while and this is a first for me, and I am bound and determined to make a 753 run this motor.


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## micromind (Aug 11, 2007)

Ok, a couple more possibilities........

What is the distance from the VFD to the motor, and is there a load reactor (preferably the dV/dt type)?

Is the cable from the VFD to the motor in its own conduit, and what type of cable/wire is it?


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## bclowman (Oct 2, 2014)

Motor is sitting in the shop less than five feet from drive. I threw in a load reactor yesterday to no effect.


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## bclowman (Oct 2, 2014)

Btw..... cable is Beldin vfd cable, copper tape shielded.


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## Jabberwoky (Sep 2, 2012)

It would be interesting to know the exact output of the 'dumb drive'. Is it running the motor in delta at 120Hz with the same magnetizing current? Is the current balanced? What carrier frequency is it using?


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## Jhellwig (Jun 18, 2014)

If I remember right hw over current is the drive current rating was exceeded. This can be caused by a high start up load. Is it flashing current limit before it trips? Make sure the mechanical end of it is free. Switching to wye might be masking a problem.

Allen Bradley drives are fussy and their tech support is a bunch of dummies.


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## bclowman (Oct 2, 2014)

Jhellwig said:


> If I remember right hw over current is the drive current rating was exceeded. This can be caused by a high start up load. Is it flashing current limit before it trips? Make sure the mechanical end of it is free. Switching to wye might be masking a problem.
> 
> Allen Bradley drives are fussy and their tech support is a bunch of dummies.


Motor has no load right now. The machining head is off of the one I have hooked up at the shop. Did play with slip compensation and acceleration times to see if it changed anything and it didnt. It goes into HW overload in less than a second. If I tell the drive it's a 4 pole it won't fault but sounds horrible.


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## Jhellwig (Jun 18, 2014)

Have you changed the motor? I have seen about every stupid problem a powerflex drive can have but yours sounds like a motor problem.

The odd thing is that it sound like a winding shorted out in the motor but powerflexes usually will tell you that a winding is shorted. Could possibly be a rotor issue in the motor but the only way to find that is a Ric test.


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## bclowman (Oct 2, 2014)

Jhellwig said:


> Have you changed the motor? I have seen about every stupid problem a powerflex drive can have but yours sounds like a motor problem.
> 
> The odd thing is that it sound like a winding shorted out in the motor but powerflexes usually will tell you that a winding is shorted. Could possibly be a rotor issue in the motor but the only way to find that is a Ric test.


Definitely drive. Motor runs like a champ with other drives. Believe it's a parameter in combination with the weird motor.


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## JRaef (Mar 23, 2009)

You are sure it is still in V/Hz control mode? It almost sounds as though it is in SVC without a valid motor model. Did you do a factory reset at some point? Because SVC is the factory default, so if you did, it will go back to SVC and then of you don't do an Auto-tune, it will act squirrely. 

On the 753, you should have parameter 35 set to "0", "InductionVHz", the factory default is "1", "Induction SV". Also, if you were programming and making changes, but did not store the changes before power cycled, you lost the changes and it went back to default settings.

One thing I like to do if I have made a bunch of changes and can't find out what I did wrong, is to perform the factory reset and start fresh.


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## KennyW (Aug 31, 2013)

Does it go into hw overcurrent when you do the autotune or does it tune ok and then trip when you try to run it? If you are not running an autotune prior to starting that's probably the issue. If it trips during autotune adjust the tune set points down.


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## JRaef (Mar 23, 2009)

He shouldn't have to do an autotune if he is really using V/Hz control though. That's why I said he should check to make sure.


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## KennyW (Aug 31, 2013)

JRaef said:


> You are sure it is still in V/Hz control mode? It almost sounds as though it is in SVC without a valid motor model. Did you do a factory reset at some point? Because SVC is the factory default, so if you did, it will go back to SVC and then of you don't do an Auto-tune, it will act squirrely.
> 
> On the 753, you should have parameter 35 set to "0", "InductionVHz", the factory default is "1", "Induction SV". Also, if you were programming and making changes, but did not store the changes before power cycled, you lost the changes and it went back to default settings.
> 
> One thing I like to do if I have made a bunch of changes and can't find out what I did wrong, is to perform the factory reset and start fresh.


V/Hz mode is squirrely on 700s and 750 drives in my experience. They still often don't start well unless you do an autotune (it updates the "start boost" and other segments of the v/Hz curves, and I think other weird stuff you can't access). I've seen this problem before and it was a bad tune. The factory settings are way too aggressive and I don't get why. 
Also, when you put these in v/Hz mode you need to make sure the "fast flux up" feature is turned off, along with a few other things sometimes. On the 700s v/Hz isn't even true v/Hz. 
These drives will fool you. Do a tune first and report back, seriously.


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## KennyW (Aug 31, 2013)

JRaef said:


> He shouldn't have to do an autotune if he is really using V/Hz control though. That's why I said he should check to make sure.


You'd think so but this is not the case. I guarantee it.


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## bclowman (Oct 2, 2014)

KennyW said:


> V/Hz mode is squirrely on 700s and 750 drives in my experience. They still often don't start well unless you do an autotune (it updates the "start boost" and other segments of the v/Hz curves, and I think other weird stuff you can't access). I've seen this problem before and it was a bad tune. The factory settings are way too aggressive and I don't get why.
> Also, when you put these in v/Hz mode you need to make sure the "fast flux up" feature is turned off, along with a few other things sometimes. On the 700s v/Hz isn't even true v/Hz.
> These drives will fool you. Do a tune first and report back, seriously.


Positive it's v/hz. I am programming from connected components. You are correct about auto tune on these drives. Although it's not SVC it does calculate certain things, VD...etc... 

Static tune is fine, but trips at start after it it's ready at auto tune completion.


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## KennyW (Aug 31, 2013)

What happens if you manually set the start boost much lower? (Say half what it calculates during the tune?) You could also try setting the speed regulator bandwidth to about half what it is.

Edit: also make sure "fast flux up" is disabled.


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## bclowman (Oct 2, 2014)

KennyW said:


> What happens if you manually set the start boost much lower? (Say half what it calculates during the tune?) You could also try setting the speed regulator bandwidth to about half what it is.
> 
> Edit: also make sure "fast flux up" is disabled.


Will do. Thanks


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