# VFD issues



## erics37 (May 7, 2009)

Rino83 said:


> it would die in the ass


:blink:


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## Frank Mc (Nov 7, 2010)

erics37 said:


> :blink:


That means it would shut down ;-) Not what you might be thinking Eric ;-)

Frank


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## BBQ (Nov 16, 2010)

Frank Mc said:


> That means it would shut down ;-) Not what you might be thinking Eric ;-)
> 
> Frank


Eric was just having a moment of reflection about the loss of his pet gerbil.


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## Big John (May 23, 2010)

I have seen significant differences in current readings trying to clamp onto the load-side of a drive because of the distortion of the waveform caused by drive operation. This will be significantly worse if the clamp you have isn't true RMS.

I've never seen it as severe as 8A to 1A, but there was enough error that I tend not to trust clamp readings and just go with what's on the display.

The problem you're describing is that you can't reverse the conveyer, even when you physically swap the load side phases on the VFD, is that right? Is there an encoder on the conveyer motor?


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## JRaef (Mar 23, 2009)

Big John said:


> I have seen significant differences in current readings trying to clamp onto the load-side of a drive because of the distortion of the waveform caused by drive operation. This will be significantly worse if the clamp you have isn't true RMS.
> 
> I've never seen it as severe as 8A to 1A, but there was enough error that I tend not to trust clamp readings and just go with what's on the display.
> 
> The problem you're describing is that you can't reverse the conveyer, even when you physically swap the load side phases on the VFD, is that right? Is there an encoder on the conveyer motor?


First thing I thought of too. If there is an encoder and someone set it up to be directional, the "option not installed" error could be telling you that the encoder pulses are not going in the right direction (sequence) that the drive is expecting to see given the encoder option selected.

But also, if there is no encoder and you are running in Sensorless Vector Control mode, the error may be related to the fact that the auto tuning procedure set up the motor model based on the windings it saw. Now you have changed the windings, so as far as the drive is concerned, it is a different motor because what it sees now does not match the model. You are not perhaps reversing the motor with a reversing contactor are you????


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## micromind (Aug 11, 2007)

Occasionally over the years, I've had trouble with CTs in Square D VFDs and soft-starts. If it's out of warranty, I've seen fault codes that didn't make sense and upon further investigation, an open CT was discovered.


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## Introyble (Jul 10, 2010)

Seen this behavior before honestly. Mind you, not telling what anybody may have done to the parameter specifications. 

Have you written down the nameplate data from the motor? If not write it down, look through your manual and scroll into the autotune menu. Make sure your motor data matches the data in the drive. Then tune the drive. Usually you have to let the rotor spin free of any load so uncouple it from the conveyor.

OH, by the way. When I have seen this what followed soon was a big boom, sounds sort of like a 12 gauge LOL


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## ponyboy (Nov 18, 2012)

BBQ said:


> Eric was just having a moment of reflection about the loss of his pet gerbil.


So nice I'm gonna thank it twice


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