Fried Volt Meter

[MikeCas]

We have an MEP 804B that runs unattended to power a submersible well pump. It has been dependable and generally trouble free for several years and about 16,000 hours of use. A few days ago it shut down after about 5 hours and we found the voltage output meter burned up. It looks like something shorted out in the meter. What could cause the meter to burn up like this? Do we have a bigger problem somewhere or is there anything else we need to check before replacing the meter and starting it up again?

 

[Scoobyshep]

electrons had a party. It looks like one connection was loose and that makes heat. You're probably fine with just a replacement meter.

 

[Guyfang]

That part often goes bad, but not like that. I have seen a few burn out like yours, but its very seldom. Like Scooby, I think you just need to replace the meter.

 

[MikeCas]

Thanks for the replies. That's what I suspected too but I wasn't sure. I have one ordered that should be here next week. Some of the other wiring close to the volt meter got pretty warm but I didn't see anything that looked liked the insulation was compromised. I will check it out and put the new meter in when it gets here and we will see what happens. Thanks again for the help. You guys and these forums are great!

 

[MikeCas]

One more question on my fried volt meter- I finally received the new one. It has a spring attached between the terminals. I don't remember that on the old one and I can't see any evidence on the burned up meter that it operated with the terminals connected with a spring. I don't understand how it could work that way. Does anyone know what the purpose of the spring connection is and should it be removed when the new meter is installed?

 

[Scoobyshep]

One more question on my fried volt meter- I finally received the new one. It has a spring attached between the terminals. I don't remember that on the old one and I can't see any evidence on the burned up meter that it operated with the terminals connected with a spring. I don't understand how it could work that way. Does anyone know what the purpose of the spring connection is and should it be removed when the new meter is installed?

Thats a shunt it creates a short to dampen movement during shipping. If you need some excitement in your day leave it in place(DONT, please find entertainment elsewhere) , Remove it before use.

 

[MikeCas]

Thanks Scooby. I don't need a lot of excitement in my day. I suspect 480 volts across that little spring would be entertaining for someone but not me.

Thanks again,

MIke

 

[Guyfang]

You will never know how many people have done just that.

 

[Scoobyshep]

Thanks Scooby. I don't need a lot of excitement in my day. I suspect 480 volts across that little spring would be entertaining for someone but not me.

Thanks again,

MIke

Anytime

Speaking from an actual observation, a 480v short not only is extremely exciting but a hazard to ones health and usually renders ones undershorts to a soiled state.

 

[Scoobyshep]

You will never know how many people have done just that.

I feel like there should be a remove before flight type tag on it.

 

[Ray70]

I've purchased more than 1 machine that still had the shunt on the Hz. gage.... luckily way less hazardous there... but begs the question, did the machine get set aside and eventually auctioned off because no matter how many NEW Hz gages they installed, none of them "worked"??

 

[Scoobyshep]

I've purchased more than 1 machine that still had the shunt on the Hz. gage.... luckily way less hazardous there... but begs the question, did the machine get set aside and eventually auctioned off because no matter how many NEW Hz gages they installed, none of them "worked"??

I call that one mans f*ck up is anothers cheap generator

I have a 501 that seemed to be fine then randomly lost power. Found out that the output lug was cracked and covered with silicone. The rubber would hold it together until it got warm then no power. I had to double my investment on a lug crimper .

 

[2Pbfeet]

I think that that spring is a "sheep from goats" / "old f%%ts vs everyone else" item. At one point, "back in the day", all precision coil driven meters were shipped with a shunt short to keep the needle movement during shipping from frying the coils, so "everyone" knew to remove the shunt (spring). Then the meter technology shifted and the knowledge rather died out, and gave some folks some very cheap generators.

Personally, I haven't been on deck for a 480V short , and I would like to keep it that way. Yikes!

All the best, 2PbFeet

 

[Scoobyshep]

Old job (funny saying that cause I'm on day 6 of the new one) someone plugged a discharge unit into the 650vdc service port (normal procedure) but didn't have the breaker in the open position so it arced and flashed over. It sounded like a shotgun going off. So yes, use brains for their intended purpose and not piss off the angry pixies

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[Summerpaws]

I think that that spring is a "sheep from goats" / "old f%%ts vs everyone else" item. At one point, "back in the day", all precision coil driven meters were shipped with a shunt short to keep the needle movement during shipping from frying the coils, so "everyone" knew to remove the shunt (spring). Then the meter technology shifted and the knowledge rather died out, and gave some folks some very cheap generators.

Personally, I haven't been on deck for a 480V short , and I would like to keep it that way. Yikes!

All the best, 2PbFeet

I was 40 feet away from a 4160v short. Fortunately there were 2 reinforced concrete walls between the event and me. I was in the control room doing logs when there was a very bright flash with a simultaneous BOOM. Also simultaneously the lights went out replaced by alarms and the sound of two gas turbines winding down. Turns out water had made it's way down some conduit and into the switchgear. You can imagine the damage.

 

[Scoobyshep]

I think the worst one I ever witnessed in person was when we vaporized a squirrel.

We had an old ballpark that the fixtures were 240 volt but each pole had a transformer to take the incoming 17,200 volt to 240. Coming into the facility it was 32k which we stepped down to 17. We blew a jack on b phase and diagnostics didn't show any trouble so we replaced the fuse and started testing. While we were waiting we saw a squirrel running down the line and he must have wanted something on the steel cross arm that the Jack was mounted to reach down and there was a bright flash and a puff of fur and that was the end of that little bastard.

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[2Pbfeet]

I think the worst one I ever witnessed in person was when we vaporized a squirrel.

We had an old ballpark that the fixtures were 240 volt but each pole had a transformer to take the incoming 17,200 volt to 240. Coming into the facility it was 32k which we stepped down to 17. We blew a jack on b phase and diagnostics didn't show any trouble so we replaced the fuse and started testing. While we were waiting we saw a squirrel running down the line and he must have wanted something on the steel cross arm that the Jack was mounted to reach down and there was a bright flash and a puff of fur and that was the end of that little bastard.

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A local employer had a reasonable size cogen plant (40MW) with a set of switch gear to connect or disconnect from the grid.

Unfortunately, they neglected to rodent proof the switch gear and one fine morning one squirrel met another one in the switch gear and plasma ensued blowing up the switch gear. So no backup from the cogen and no backup from the grid. "an unanticipated event"

As it turned out, there was one prebuilt switch of the right specifications in the world. It happened to be on the other coast. IIRC it took a week, but that was way better than the reported six month lead time from the manufacturer in Italy. I stood next to a senior person as they recommended firing up a generator in a hallway with no ventilation in the building. It was crazy.

For some reason, I have always been a fan of rodent proofing power equipment...

All the best, 2PbFeet

 

[Summerpaws]

I think the worst one I ever witnessed in person was when we vaporized a squirrel.

We had an old ballpark that the fixtures were 240 volt but each pole had a transformer to take the incoming 17,200 volt to 240. Coming into the facility it was 32k which we stepped down to 17. We blew a jack on b phase and diagnostics didn't show any trouble so we replaced the fuse and started testing. While we were waiting we saw a squirrel running down the line and he must have wanted something on the steel cross arm that the Jack was mounted to reach down and there was a bright flash and a puff of fur and that was the end of that little bastard.

Sent from my SM-S908U using Tapatalk

I shouldn't laugh, but.... The last 2 power outages we've had were both caused by squirrels.

 

[Mullaney]

I shouldn't laugh, but.... The last 2 power outages we've had were both caused by squirrels.

.
Yep... That was our last power outage here as well. I looked up and saw the fuse hanging open. walked around - and down on the ground was a gray fuzzy ball. Called it in and gave Duke Power the info. They sent a little bucket that the guy didn't even deploy. Just snapped in a new fuse and we had power again...