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#10768 - 06/18/02 05:14 AM harmonic noise?
Mustang Offline
Junior Member

Registered: 06/07/02
Posts: 2
Loc: shelbyville, Indiana USA
We have a degater machine(240v 3 phase) that has a AB variable frequency drive. Anywhere we plug this machine up it sends a lot of noise all the way back to the panel and affects the other equipment coming off that panel, digital displays go nuts! what can I use to get rid of this?

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#10769 - 06/18/02 08:38 AM Re: harmonic noise?
Redsy Offline

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
What model Drive is it?
AB makes Line Reactors to help mitigate harmonics which are fed back into the power line from the Drive.
MTE corp. offers the same, and are quite a bit cheaper.
They are not expensive at all. I believe a 10 HP unit costs less than $150.00

[This message has been edited by Redsy (edited 06-18-2002).]

#10770 - 06/23/02 07:50 AM Re: harmonic noise?
Bjarney Offline

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
I would be asking questions of the ‘degater’ {what is that?} supplier, and maybe AB could help in that they are interested that their products are applied correctly. Sounds a little fishy though. Make sure to get a copy of AB’s drive installation instructions and see that it is installed exactly to their specs. Get ready for some finger pointing. Proceed carefully. If your job was to provide a powered receptacle for the degater, you can probably, by rights, walk away from it as you are done with your assignment.

But then, it could be a good experience finding out what the exact problem and cure is. Get straight exactly who pays for what early on. It’s extremely difficult to remotely troubleshoot an odd problem, but make notes on who said what if you take on the troubleshooting task. If possible, be there when the degater expert works on his machine. Be wary of things like oddball/non-code grounding [or ungrounding.] Their obligation is to provide a working piece of equipment that doesn’t interfere with other stuff that is/was OK before degater powerup.

Reputable equipment suppliers will usually pay you for your work in fixing their problem, but get that cleared up early on, because they might get flakey at some point. Do not change anything on the degater unless you have written instructions from ‘degater central,’ and that you understand exactly what they want you to do.

Study up on it Mustang, but generally there are 3% and 5% reactors. In your case it probably needs to be installed wired between the panelboard and drive. It may need to be configured so that control power on the degater is fed upstream of the reactor…you may have to experiment—no guarantees. In extreme cases a Ä-Y drive-isolation transformer may be required.

[This message has been edited by Bjarney (edited 06-23-2002).]


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