This Happened Today!

mk42 said:

Got a call the next day from the power company saying "oops our bad, but we won't pay for any damages".

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Is this legal??

Happens all the time here in the south... it was so bad we shut down when storms were in the area, they eventually put in a substation and that helped a lot but we would told "sorry" , we would lose 50 - 100k every time we would get a glitch so it was better to do a controlled shut down

We had a transformer blow here one year during a storm I had to grab the fire extinguisher to put it out because the security guard panicked and kept walking past it.

Next step...
Go to your power company, and have them replace the drive.
With in-succession power outages, sometimes the precharge circuits in the drive think everything is good, when it isn't, and just dump full rectified line voltage to the bus capacitors, which eventually explode.
Having an external contactor, actually supply the drives helps a lot. We don't let AC power to be applied to VFD's for 5 minutes after any power outage.

What is it with power supplies in the states?

janner_10 said:

What is it with power supplies in the states?

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1930's technology that is pushed past it's limits. Way past!

PLC Pie Guy said:

Wear you PPE kids, and play safe!

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+1

I have a friend who was at the wrong end of a whole series of unfortunate coincidences and copped an 11kV arc flash. He was in a coma for several weeks, but one of the many surgeons and doctors who brought him back from the brink mentioned at one point "well, there's no sign of his safety glasses, but he was obviously wearing them because the only hair left on that whole half of his body is his eyebrows"

I'll tell you a funny one.
I worked as a maintenance electrician in a big factory and I was very green back then.
From day 1 the foreman took a dislike to me.
The breakdowns were allocated by him and he sorted through them to make sure I got all the bad ones.
Not only that, he secretly followed me to spy how I went about it.
I say secretly, he wouldn't have ever made a spy because I knew he was there.

A motor was randomly tripping. I tested it and it all seemed well. I ran it and after a while it tripped again.
I took the motor off, still connected and ran it on the floor - it still ran then tripped.
I had the terminal cover off and eventually I noticed blue flashes from within the motor.
Sometimes I saw them sometimes I didn't.

It was all too much for the foreman - he was sure I was messing about and suddenly popped up.
I told him about the blue flashes and he was very sceptical
I ran it again while he watched and it tripped.
From my angle I saw blue flashes but him being right above didn't

He knelt down by the terminal cover and said run it again.
I did and there was an almighty bang with flames shooting out of the terminal cover.
His eyebrows and eyelashes were gone.
Shouldn't laugh but his little black (formerly white) Al Johnson face was unbelievably funny.

We all know what I should have done in the first place - but as I said, I was incredibly green back then.
The rotter tried to get me the sack saying i'd done it on purpose (he failed)

I was working for an electrical construction contractor out west when I was in the IBEW. The attitude then was get it done, and if you can't work it hot, then you need to find a different line of work. Anyway, the apprenticeship program had some pretty strict guidelines as to when the apprentices could start working hot panels and switchgear, etc. One young man had just gotten to the point of having permission to work hot gear, and was disassembling an MCC at a hospital. It was locked out of course and de-energized, however there was a parallel bus below the one that was locked out. His ratchet touched the live bus bar when he was reaching in an access bucket and he wound up being burned on both arms quite badly. Good thing he was right at a hospital. Spent over 7 months in the office. Needless to say, new guidelines for hot work. Too little too late.

I worked here in Detroit at a cement plant. There were 3 - 13.8KV mill motors, across the line start. Used 35 year old GE Magna-blast motor operated breakers. You had to stand in front of the breaker cubicle and operate a switch on a DC motor that would rack in and rack out the breaker. When you tested the breaker before install it would remain charged (closed). So when racking it in it would automatically trip and scare the **** out of you the first time. GE named them magna blast for a reason. One faulted and blew parts and oil all over the MCC room and completely bent the cubicle door. I asked one of the electricians one day what would happen if the breaker didn't trip or go open when we racked it in, would the motor try to start? No answer, so I assumed yes. I've dodged so many bullets my back hurts from bobbing and weaving. PPE was offered and available, but not required. Hmmm.