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Re: 50 KVA Pole Pig
No problem, the circuit breaker (CB) feeding the pig is presumably sized to
handle a dead short at the CB's terminals. Since the pig is downstream from
this point, the wiring impedance (between the CB and the pig) will further
decrease the available current. The pig itself cannot increase the
Short-circuit current.
Tesla List wrote:
> Original Poster: Jim Monte <JDM95003-at-UCONNVM.UCONN.EDU>
>
> Jason,
>
> Those pigs will not be any harder to ballast than their smaller cousins.
> Something you may want to look into with such a large transformer is
> the ability of your circuit breakers or fuses to open if it is
> accidentally shorted. This will be determined based on the percent
> impedance of the transformers, the impedance of the wires leading to
> the transformer, and the interrupt rating of the breaker/fuse.
>
> As I understand these ratings (and if there are any errors, someone
> please correct me) here is an example assuming a typical percent
> impedance of 1.5%:
>
> 50 kVA / 240V = 208.3 Amps at full load
> 208.3 Amps / 0.015 = 13,889 Amp drawn by the transformer when the LV
> side is connected to an ideal voltage source and the HV side is
> shorted.
>
> Typical circuit breakers for residential use are rated to interrupt
> up to 10,000 Amps, and fuses up to 20,000 Amps. So if the wire
> supplying the transformer is heavy enough, you may have some problems
> if you are using circuit breakers.
>
> Jim Monte
> > I recently came upon a total of three 50 KVA, RTE (brand?) pole pigs
> >that I can have for free
> > I have access to 2 pulse rated caps at .05uF-at-50KV and can build a
> >rotary gap if needed. I have a feeling that the pigs are overkill, but
> >who can resist free!
> >
> >Please give advise soon, I have to pick them up this week if I want
> >them.
> >
> > Thanks
> >
> > Jason Zuberer
> >
> >