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Re: Pole Piglets (what are they good for?)
Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>
If you find one at the right price, jump on it! These "piglets" are used
to provide low voltage power for relays and signaling for pole top
control applications. As an example, utilities often have a need to
switch power factor correction (PFC) capacitors into or out of a circuit
depending upon variable downstream loading conditions. While oil or
vacuum contactors perform the actual switching function, the relays are
usually powered from a small oil immersed outdoor control transformer.
These look much like distribution transformers, only they are
significantly smaller and lighter weight. These are rated at 0.5 - 3
KVA, and are typically sold as part of a complete pole mounted PFC
package. Control transformers are sometimes used to supply power to
isolated pole lighting or other small loads. Next time you see a pole
mounted PFC bank, look closely for cylindrical cans with top mounted
insulators - there are typically three "cans" that contain the oil
switches, and one that is the control transformer which powers them all.
Other than handling lower power, these transformers are otherwise every
bit as tough as their larger cousins, and are often less expensive than
an equivalent Potential Transformer. And, in similar fashion, they can
also be pushed to 2-3X their faceplate rating for TC use.
-- Bert --
Coins Shrunk Electromagnetically!
Tesla list wrote:
> Original poster: "Gregory Hunter by way of Terry Fritz
> Dear List,
> I was browsing the inventory list on the T&R Electric
> and found listings for 3KVA and even 1KVA polemount
> transformers. Their application for coiling purposes
> is obvious enough--IF you can convince T&R to sell you
> one and IF you can afford one. But of what earthly use
> are they in an industrial/commercial application? Who
> is buying these baby pole transformers, and what are
> they good for?