I recently conducted an airborne ultrasonic survey of our plant's 480 volt MCC. I didn't open any cabinets but scanned the outside with an Ultraprobe 10000. I didn't really expect to find anything, but I discovered several breakers that had unique sounds. I'd to be able to give more info to my maintenance electricians other than just a simple "noisy breaker". I'm only going to attatch one wave file but I have several others if anyone is interested. Any help would be appreciated.

K1bkr515.wav (343 Kb, 93 downloads)

I have had a look at your file and it is severely distorted - I would not like to hazard a guess as to why, but the signal is heavily clipped and looks to be undersampled.
I know nothing about the UE10000, the problem I see in your wave file is the sort of problem I see when people use auto gain control on an MP3 recorder.
Do you have some way of looking at the siganl you are recording and reducing the input gain? If not, do you have a vibration data collector that you could set up instead?
Best Regards,
Tom Murphy

Regardless of the sound 480 should not make any noise. Open the panel and view it visually to locate the problem. If you can open the panel while it is still online use the UE10000 with the rubber focusing cone and scan, "BEING EXTRA CAREFUL" not go past the permimeter of the door with the instrument.
After listening to the sound it does sound like tracking and at 480v no corona is present. Only possibility is arcing and/or tracking.
Whats missing for it to sound like tracking is the typical build-up of intensity, discharge and start over. In any case, 480v should not make noise unless it has a breaker on a timer. Perhaps you have dirty gear in need of a little dusting and cleaning or carbon build-up on one or both legs of the breaker.
Let us know what you find.

Dasteve,

If you can open the panel and have access to a Thermography Camera you may be able to confirm the fault..

Have a nice day and Happy New Year!!