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Re: Three Phase Generation and transformer
Original poster: Bert Hickman <bert.hickman@xxxxxxxxxx>
Tesla list wrote:
Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
Hello All,
I am nearing completion of my 3 phase 20KVA Diesel powered
generator. Yup, Portable power! The generator is currently wired
277/480V Wye. I have a 480v delta to wye step down transformer which
would then be 208/120 (with neutral). My HV supply wants to see 208v
3 phase and a neutral which in turn supplies 28KVDC.
* is it ok to connect the generator 480v wye (sans neutral) to
the Delta Primary of the step down transformer?
Driving a Delta load from a Wye source should be OK as long as both
are rated at 480 volts phase-to-phase...
* If so, how should the wye generator, delta-wye step down
transformer, and wye HV step up transformer be grounded?
Connect the neutral of your generator, the neutral of your step down
transformer wye output (and thus the neutral to the LV side of the HV
transformer) together and earth the combined connection at a single
point via a ground rod. In general, the chassis of the generator and
frames/cases of the transformers should also be bonded together and
grounded. Specific details covering grounding are covered in National
Electric Code (NEC) section 250 - Grounding (section 250-6 deals with
portable generators). A copy of the National Electrical Code Handbook
would also be useful... your library should have the latest copy.
Does anyone know?
Thanks,
Jim Mora
Good luck and play safely,
Bert
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