Re: Pole Pig Question
Tesla List wrote:
> Original Poster: "Ryan Ries" <spud-at-wf-dot-net>
> Hey. In my search for a distribution transformer, a couple of questions
> came to my mind. First of all, I have observed that single-phase
> transformers only have one high voltage terminal, while triple-phase
> transformers have two. Aside from that, what are differences? (I guess
> I'm asking for the theory behind the different phases of AC current.)
> Also, some of the transformers have primary voltages that I can understand.
> For example, 12470 volts. Others have weird things like 7200/12470Y, or
> 12470GY/7200. Could you please explain this to me also? I have a feeling
> it has to do with the 1-phase and 3-phase thing, but I don't know.
Single phase pole transformers come with either one or two bushings, the number
of bushings having nothing to do with the phase of the transformer. A single
bushing transformer has one end of the high voltage winding tied to the case.
If you get a single bushing transformer, BE ABSOLUTELY CERTAIN, that the case
is grounded, otherwise it (the case) will be at high voltage potential. It is
best to find a two bushing transformer.
The Gnd Y/Y designations are for power company connections between one leg of a
three phase line and ground. The transformer will only produce the voltage
without the Y designaton, which is the lower of the two voltage ratings, when
run in reverse for Tesla coil operation.
Ed Wingate RATCB