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Re: Pole Pig Question
Hi Paul,
> Original Poster: "Paul Eugene Kidwell" <tmb-at-ieee-dot-org>
> I was about to ask this very question. Here are 2 listings from
> Austin International's webpage:
> 15 KVA, Primary Volts 7.2 X 19.9, Secondary Volts 120/240, Taps N.T.
>
> 15 KVA, Primary Volts 7200, Secondary Volts 120/240, Taps N.T.
>
> 10 KVA, Primary Volts 7620, Secondary Volts120/240, Taps T.B.
> So from what you're saying, the top one woul be 3 phase (and therefore
> not easily usable) and the bottom 2 would be single phase, correct?
> Any idea what the difference between a N.T. and a T.B. tap is?
No, a three phase UNIT (an xformer which has 3 sets of coils
for each side internally) should be avoided. If you can get a
pig that CAN be used in a 3 ph. wiring scheme (see Jimīs great
explanation today), BUT only has ONE set of coils internally,
by all means, use it. This kind of xformer is easy to identify
by the double markings such as 7200/12470Y or 12470GY/7200.
and by looking at the number of connections. N.T. means no taps.
The low voltage side only has 3 connections (120V-0V-120V).
Taps are used to compensate for wiring and distance losses. They
raise or lower (usually marked in %) the LV side by a few volts.
This is a neat addition to have, but not necessary. To me, it would
be worth an extra $5-$10, but not more. As to T.B. ?? BM (beats
me;o}). I have to admit your first xformer has me a little stumped.
It doesnīt fit a Wye or a delta 3 phase circuit (the voltage
difference is too high between 7200 and 19900 volts). Do you
have any idea how many connections it has? It may be that there
is a tap (or even better: two HV windings) at 7200 volts. If so,
this pig would have 3 or 4 horns. IF this is the case, I would
consider getting it. That way you can start out small and work
your way up. Would be nice to have another "low" voltage coiler
on the list to help me kill the myth that low voltage coiling
doesnīt work ;o)).
Coiler greets from Germany,
Reinhard
Ouch, my finger tips are bleeding today ;o)