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IBEW L.U. 1852
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Thanks for the cool pics......I miss that kind of work.
 

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Discussion Starter #8
From what I have seen it's 1200VAC 3PH and this is the will make motor #7 the other 6 were installed in 1995. To who ever asked, each motor is 20000hp.
 

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That's a ton of copper for the motor feeders! The 25,000 hp I did a few years ago was 15kv and parallel single conductor 500's feeding it...
 

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bkmichael65 said:
1200 volts? Is that a typo? I would think it would be a lot higher than that
I hope to shout its a typo, otherwise the motor FLC is going to be around 12,000A!

Probably 12kV.
 

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The wiring looks like single conductors.. Just asking, is there a requirement in the NEC for cable layouts for single conductors? I remember a table in the CEC for the configuration, and spacing needed...
 

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Ozzy1990 said:
Pretty sure its 1.2KV, the jacket on the cable said it was only good to 2.4KV
Is this the Nucor rolling mill? If so, I believe those are 1200VDC motors, fairly common in large DC motors because I think that's the limit of practicality for DC. Might be getting fed with 3phase AC, likely 12.47kV, but there would be transformers ahead of the rectifiers inside of the drive system. They will have multiple phase shifting transformers feeding multiple rectifiers to reduce the harmonics caused by the rectification, but if the jacket you read was on the output side, it would point to the motor being DC.

Still one hellofa motor. Pulling and terminating all of those cables must have been a chore! I did some work on a 37,000HP motor at a Boeing wind tunnel, that had a 15kV class VFD on it and almost everything was connected with hard busbar. At the time, it was the largest AC motor and drive in the world. It's not any more though.
 
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