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RE: What is a "pole pig"?



Original poster: "Pete Komen by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pkomen-at-zianet-dot-com>

Rick,


The answers may be in the tesla list archives, but...

A "pole pig" is a distribution transformer rated around 10KVA (for TC use)
with 240V secondary and 14,400V primary (primary and secondary reversed for
TC use).  It hangs on a power pole (thus the "pole" part, "pig" because of
the large rating and weight compared to smaller transformers).

An NST has shunts that divert some magnetic lines from linking to the
secondary.  These shunts give the NST primary enough impedance to limit the
primary current even when the secondary is shorted.  The pole pig is
designed with all the coupling possible and the current is limited only by
the impedance of the load.  In a TC that impedance is often low and if the
pig is not current limited externally, it will blow breakers.  Current is
limited in the pig by connecting the 240v primary in series with an inductor
(and/or resisters).  The external inductor (often a welder with the
secondary shorted) is called the "pole pig ballast".

Regards,

Pete Komen

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, January 17, 2002 8:02 AM
To: tesla-at-pupman-dot-com
Subject: What is a "pole pig"?

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<KLogan2026-at-aol-dot-com>

    I know I'm a beginner and all, but what is a "pole pig"?  Is it a
transformer or what. And what is meant by "pole pig ballast"?
    Thanks
    Rick Logan
    klogan2026-at-aol-dot-com