Noisy Locate.

[ptonsparky]

Doing a cable locate for a feedlot. The wand was picking up a lot of noise so we shut things down until we located which VFD was causing grief. A quarter mile away, fed by a different transformer bank. The only common is a EGC to a transfer switch. What part is failing that can cause such interference?

This is the Pump installers problem at the moment but I'm curious.

 

[Low-impendence2017]

Are the loads linear or nonlinear? Or both

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[ptonsparky]

Are the loads linear or nonlinear? Or both

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The VFD causing the problem would be nonlinear.

 

[Low-impendence2017]

Have you tested with oscilloscope?

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[ptonsparky]

Have you tested with oscilloscope?

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No.

 

[Low-impendence2017]

Is the vfd existing or new install?

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[ptonsparky]

Is the vfd existing or new install?

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Existing.

FWIW, the pressure transducer had failed so the drive is running at a default of 30 HZ.

 

[Jraef]

Can you determine if the noise is from the input or output of the drive? In other words which cables are you picking it up on?

 

[Low-impendence2017]

Versus 60 where it should be. Makes sense

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[Low-impendence2017]

Glad you got it figured out

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[Low-impendence2017]

Can you determine if the noise is from the input or output of the drive? In other words which cables are you picking it up on?

Something I found if your meter allows it. Try this
http://en-us.fluke.com/training/tra...sure-frequency-with-a-digital-multimeter.html

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[ptonsparky]

Can you determine if the noise is from the input or output of the drive? In other words which cables are you picking it up on?

I am guessing the line side. We've done locates here many times without the noise. The well VFD is fed from a separate overhead transformer bank than the rest of the feedlot. The arrangement with the transfer switch allows for power from either transformer bank or the lot standby generator. The common would be the primary neutral and the EGC from the transfer switch.

The noise generated sounds very much like what you would hear standing in front of it.

 

[ptonsparky]

Something I found if your meter allows it. Try this
http://en-us.fluke.com/training/tra...sure-frequency-with-a-digital-multimeter.html

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I have several that are capable and an older PQ meter if need be.

 

[kwired]

RF filtering needed?

How big of a drive/motor?

Any other "path" between where you were and the drive besides MGN?

 

[Jraef]

Yeah, I'm thinking an EMI/RFI filter for it too. Some drives come with it built-in so you might not be used to having to deal with it, others don't. If you share the make and model I can tell you.

 

[ptonsparky]

RF filtering needed?

How big of a drive/motor?

Any other "path" between where you were and the drive besides MGN?

Filtering is a thought but why all of a sudden?

Drive output is 27A,21KVA, 480v. Input is 33 A. Guessing 20 HP.


The EG is buried directly below the overhead primary.

The VFD is almost silent (remember there are No crickets at my house) when running.

 

[ptonsparky]

Yeah, I'm thinking an EMI/RFI filter for it too. Some drives come with it built-in so you might not be used to having to deal with it, others don't. If you share the make and model I can tell you.

Yaskawa iQ pump. cimr-p7u4011.

The manual talks of when adding an RFI filter make sure not to connect it to the load side of the drive, so I am guessing, no they don't have one.

 

[Jraef]

Yes, the Yaskawa P7 drives do NOT come with what they call an "EMC filter" (EMC = Electro-Magnetic Compatibility), it is an accessory that you must buy. You don't have to buy theirs however, you can buy them from others, such as TCI (I happen to like theirs, but none of them are bad really).

Why this installation and not others? No way to tell for sure, but it's most likely about the system grounding and the way the ground connections were made. That's why they sell the filters, it's also why some VFD mfrs just go ahead and build them into their product whether you want them or not.