Disconnect Melting

[TwoBlocked]

...

Use an overlapping control contact at the disconnect to ensure the drive run command is off before the power is interrupted.

Yep

 

[tortuga]

After the 1st time we ran a bunch of calculations and made sure wire sizing/distance/etc was all good.

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?

 

[ptonsparky]

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?

OPs followup has been very good but, Yes, we want more!

 

[herding_cats]

C phase is bottlenecked somewhere. If it killed a 200A DC something else is wrong.

 

[Joethemechanic]

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.

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

 

[Joethemechanic]

C phase is bottlenecked somewhere. If it killed a 200A DC something else is wrong.

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

 

[herding_cats]

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

Like tons of reactive power? Yeah put a scope on it.

 

[winnie]

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

I think a VFD supplying a large fan counts as 'lots of rectification'