300KVA Transformer photos - ECN Electrical Forums

Quote

All,

I have viewed your website a lot of times and watched in amazement at some of what is posted. I'd rather watch, however, a transformer started making some funnny noise when I was on site, and I de-energized it without permission. Attached are some of the photos, pay close attention to phase A.

Dennis W.
Minneapolis

There could be a slight problem with that.

Ahh good catch there.

i am suprised that it did not trip the OCPD yet

Merci, Marc

Good call to shut it down.

Looks like a loose connection in that jumper, overheated and arced away the flat tab of the lug and terminal of the TX.

Cheers

Raymond

Dennis W:

A question: Can you describe the "funny noise"? I have a theatre with a similar Tx that makes a peculiar high-pitched buzz/whine..didn't notice any burning smells but it sure is loud!

Good call. I'd say that transformer would be pretty noisy anyway, what with the hard-piped connections. I'd guess the funny noise would be something other than 60Hz plus harmonics, no?

For a 300KVA xfr, the secondary conductors seem a little on the wimpy side??

300KVA is usually 800 amp secondary MOCP @ 208 volt, 3 phase.

Oversized xfr?? Not that it matters now, but I'm curious.
John

Ah, I have seen this before - the "Melti-tap" transformer.

When I was younger and far stupider than I am today. I did a service call for mixed voltages at a supermarket, and went all over trying to find the place that had a neutral - all the way back to the transformer and pulled the cover off (LIVE - DUMB) to find a glimering molten pool of Aluminum. Do ya know that feeling like you're looking at a nest of angry hornets close up? "I'll just put this cover back on with 2 screws, and get away from this fast..."