Disconnect Melting

JoelHunter1102 said:
After the 1st time we ran a bunch of calculations and made sure wire sizing/distance/etc was all good.
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Can you share your calculations?
What is the fan motor namplate rated voltage / HP.
Branch circuit size / breaker size?
You mentioned the wire is copper what is the wire size?

You mentioned the fan is 15 feet away from the disconnect.
How long is the run to the disconnect?

You mentioned you monitored the voltage was that on each phase L-L?
 
tortuga said:
Can you share your calculations?
What is the fan motor namplate rated voltage / HP.
Branch circuit size / breaker size?
You mentioned the wire is copper what is the wire size?

You mentioned the fan is 15 feet away from the disconnect.
How long is the run to the disconnect?

You mentioned you monitored the voltage was that on each phase L-L?
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OPs followup has been very good but, Yes, we want more!
 
ptonsparky said:
Do away with the reducers and put in 110 amp fuses.
rk
What is/are the actual loads? Types.
Single, three phase? Mixed loads?

I have no idea what an indoor shooting range requires. My outdoor is a 1/2 mile and requires daylight.
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Light up the target a little bit with one of those little rechargeable work lights. If it's too bright smear something on the lens.

I like shooting at night
 
herding_cats said:
C phase is bottlenecked somewhere. If it killed a 200A DC something else is wrong.
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I think I'd want to record current on all 3 phases for a few days and then look for something that deviates from the norm. Probably want to do voltage too.

I wonder if there is anything in the circuit like line reactors or PF caps? Or if it's supplying something something with lots of rectification
 
Joethemechanic said:
I think I'd want to record current on all 3 phases for a few days and then look for something that deviates from the norm. Probably want to do voltage too.

I wonder if there is anything in the circuit like line reactors or PF caps? Or if it's supplying something something with lots of rectification
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Like tons of reactive power? Yeah put a scope on it.
 
Out of Curiosity I would swap the phases and see if another phase burns up the same way. I believe the VFD can be programmed to correct rotation. If not just swap both line and load phases to correct rotation.

I know this is a simple approach but I would want to see if it happens to another phase.
 
Vinny B said:
Out of Curiosity I would swap the phases and see if another phase burns up the same way. I believe the VFD can be programmed to correct rotation. If not just swap both line and load phases to correct rotation.

I know this is a simple approach but I would want to see if it happens to another phase.
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The output of the VFD won't change.
Yes, if the problem follows, it's the load. Might be better to take all voltage, scope and thermal measurements before and soon after.
Waiting another three years will keep us waiting with abated breath.
 
I've flown a over 1000 miles to go put eyes and hands on mysterious problems like this, and most times it's somebody doing something stupid and whatever I'm being told on the phone seems to be something from an alternate reality
 
Joethemechanic said:
I've flown a over 1000 miles to go put eyes and hands on mysterious problems like this, and most times it's somebody doing something stupid and whatever I'm being told on the phone seems to be something from an alternate reality
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Read HVAC tech story recently, guy determined gas valve was bad. Unit was rather old and he talked client into replacing the furnace. New furnace wouldn't fire after it was ready for run. Found out the gas company had disconnected service. You would think they would have figured that out before determining old unit had a bad gas valve?
 
Back when I was a kid, we moved into a new house. First thing my dad did was put a window AC in. Thing made noise but didn't work.

Replaced the AC. Thing made noise but didn't work.

The 6-15 receptacle had been wired 120V. Whoops.
 
winnie said:
Back when I was a kid, we moved into a new house. First thing my dad did was put a window AC in. Thing made noise but didn't work.

Replaced the AC. Thing made noise but didn't work.

The 6-15 receptacle had been wired 120V. Whoops.
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Kind of worse yet, I had a builder change one my temporary 5-15 GFCI receptacles to be supplied by 240 volts.

Kind of hard on equipment that gets plugged in that is expecting 120 volts. I was a little surprised the GFCI circuitry survived that and still worked.

He had an air compressor that was dual voltage that had a external switch to easily change over winding taps. He had a 5-15 plug on the cord so he could plug in most anywhere but also knew that it often would trip the breaker on 120 volts and apparently would just change the configuration when possible to run it on 240 volts and do whatever he needed to get 240 to the receptacle and leave his cord as is.:censored:
 
I usually figure the place of the heat is the place of the problem. But this is kinda weird
In that you have replaced the disconnect several times. I might want to switch legs to find if the problem travels.
Not sure why it would but a guy I once worked for had said "Do something even if it's wrong but do something."
 
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