I have a 3 phase 480v 2000a main lug only switchboard being fed from a wye secondary of a 1500KVA three phase oil filled transformer. The primary voltage is 2.3kv. There are three fusible disconnects on the switchboard feeding three soft starters each driving a three phase squirrel cage motor...
We wanted to move an existing conduit for a 2300volt 250hp motor. The original conductors were 5kv nonshielded EPR insulation, in steel conduit in free air. We now want to move it underground in steel conduit. I called the local wire and cable distributor and it seems I have two options. There...
We have a 7MVA electric arc furnace transformer that uses water cooled jacketed cables to feed our electrodes. Each phase has two paralled conductors connecting from the secondary bus 275v 17,000 amps to our electrode holders. At times we don't get enough water flow to one or both of the...
Hello,
I currently have a 2,300v 250hp squirrel cage motor being fed from an across the line starter. No VFD's- nothing fancy. My company wants me to reroute the motor feed, which is now in steel rigid conduit running across the building structure to the motor. They want me to take it...
My corporate safety manager called me yesterday asking me a bunch of questions concerning hipot testing. Our company builds the towers for wind turbine generators. We supply the bus from the top down to the bottom and have to prove the insulation passes before they hook up the generator. I have...
I have a question concerning harmonics. We have a 240v single phase lighting panel that is feeding some 400w metal halide high bay lighting fixtures. The main CB is 100A and the branch circuits are 20A. When all of the lights are turned on the main breaker is seeing about 50 amps. Each of the...
I have been asked to put in an emergency stop or disconnect switch on a 120v 1 hp pump motor that dispenses deisel fuel from a 300 gallon tank. The motor itself is UL listed for Hazardous Locations, and there is a manual motor starter built right into the pump for making and braking the power to...
I am an electrical guy, so please bear with me. I work in a steel foundry in Pittsburgh, PA. It's freezing cold right now. The ambient temperature is getting down into the teens, even inside of the mill. The last 2 days we have had some downtime due to solenoids freezing up, both in the same...
I am an elcetrical guy so bear with me. We are a steel foundry that uses a Corewash paint made by Ashland Chemical Corp. The paint is Velaplast ZWTXB 8090 Coating. We are using a double diaphragm pump to transfer this liquid paint into a corewash station which has jets to spray and coat our...
I started up a used 300HP 480V screw compressor and found that my programmable overload relay is bad. It is a square D motor logic plus cat# 9065 SP64. I can't find one anywhere. Does anybody know where I can get this unit? I like this model because no porgramming software is needed. I have a...
We are an industrial facility that has many electric arc welders. One of our plants is using SO cord wired directly from the welder to a disconnect. Reading into articles 400.7-400.8 and 368.56 I came to the conclusion that they have to have a permanantly mounted receptacle fed from the...
