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RE: usable potential transformers? (fwd)
---------- Forwarded message ----------
Date: Tue, 03 Jul 2007 01:09:36 +0000
From: David Rieben <drieben@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Cc: drieben@xxxxxxxxxxx
Subject: RE: usable potential transformers? (fwd)
Hi Rich,
It sounds like you just have a laser power supply transformer ;^)
Obvioulsy it's designed for its primary input to be placed across
two 120 volt phases, which will yield 208 volts (120 x sq.rt. of 3)
Potential transformers are generally made to measure a known
fraction or ratio of a primary line voltage since standard instru-
mentation cannot withstand the multiple kVs of primary line
voltages. In every case that I've seen, the standard secondary
instumentation voltage output (input for us) for all potential trans-
formers (PTs) is 120 volts. PTs' are classified by their primary/
secondary turn ratios: for example, a 60:1 PT is designed for a
7200 volt input and of course a 120 volt output, a 120:1 PT is
designed for a 14,400 volt input and a 120 volt output, and so on.
Also, as someone else has already pointed out, most PTs have a
pretty low kVA/mass ratio since they are designed with relatively
large cores to achieve very precise voltage regulation for a wide
range of loads.
David Rieben
-------------- Original message --------------
From: "Tesla list" <tesla@xxxxxxxxxx>
>
> ---------- Forwarded message ----------
> Date: Mon, 2 Jul 2007 17:21:57 -0500
> From: Rich & DJ
> To: 'Tesla list'
> Subject: RE: usable potential transformers? (fwd)
>
> I am asking for a little help in understanding. I am not an electrician or
> EE. I guess I spoke out of turn about 208v. A transformer I have on a coil
> is 13Kv at 1.9Kva with a 208Vac input, it is from a laser. I remember when I
> was working some of the computer rooms were had 208v. I thought it was used
> more often.
> Rich from the middle of Missouri.
>
> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Monday, July 02, 2007 4:32 PM
> To: tesla@xxxxxxxxxx
> Subject: RE: usable potential transformers? (fwd)
>
>
> ---------- Forwarded message ----------
> Date: Mon, 2 Jul 2007 13:54:58 -0700 (PDT)
> From: Yurtle Turtle
> To: Tesla list
> Subject: RE: usable potential transformers? (fwd)
>
> In my industry, most everything is 480. We consider
> 208 a bastard, that is pretty much useless for large
> motors. Over 500 - 600 hp, we use 4,160.
>
> Adam
>
> --- Tesla list wrote:
>
> >
> > ---------- Forwarded message ----------
> > Date: Sun, 1 Jul 2007 19:57:06 -0500
> > From: Rich & DJ
> > To: 'Tesla list'
> > Subject: RE: usable potential transformers? (fwd)
> >
> > Are you sure it is not 208V input, that is a
> > standard voltage for industrial
> > transformers. My PT transformer is 208 input.
> > Rich
> >
> > -----Original Message-----
> > From: Tesla list [mailto:tesla@xxxxxxxxxx]
> > Sent: Sunday, July 01, 2007 12:16 PM
> > To: tesla@xxxxxxxxxx
> > Subject: RE: usable potential transformers? (fwd)
> >
> >
> > ---------- Forwarded message ----------
> > Date: Sun, 1 Jul 2007 09:37:21 -0700 (PDT)
> > From: J. Aaron Holmes
> > To: Tesla list
> > Subject: RE: usable potential transformers? (fwd)
> >
> > Yeah, hard to read. I think the VA is 1750. At
> > least, I can't think of what else that number would
> > represent...
> >
> > Aaron, N7OE
> >
> > --- Tesla list wrote:
> >
> > >
> > > ---------- Forwarded message ----------
> > > Date: Sun, 1 Jul 2007 09:03:52 -0700
> > > From: Jim Mora
> > > To: 'Tesla list'
> > > Subject: RE: usable potential transformers? (fwd)
> > >
> > > Hi All,
> > >
> > > Yes, I was looking at (1) of these, though $'s are
> > > tight now. I have put in
> > > a request to the seller find out the VA rating
> > since
> > > the plate is
> > > unreadable. I am assuming (always dangerous) that
> > > the Pot xformer is
> > > removable from the apparent stand. It would be
> > nice
> > > to go up to this voltage
> > > but quenching even on a 17" rotor, may become an
> > > issue??
> > >
> > > Thoughts?
> > >
> > > Long arcs,
> > > Jim Mora
> > >
> > >
> > > -----Original Message-----
> > > From: Tesla list [mailto:tesla@xxxxxxxxxx]
> > > Sent: Sunday, July 01, 2007 7:01 AM
> > > To: tesla@xxxxxxxxxx
> > > Subject: usable potential transformers? (fwd)
> > >
> > >
> > > ---------- Forwarded message ----------
> > > Date: Sun, 01 Jul 2007 08:41:00 -0400
> > > From: Dave Goodfellow
> > > To: Tesla list
> > > Subject: usable potential transformers?
> > >
> > > On ebay now Item number: 220125509946
> > > Looks like 25000 to 120, but it is hard to see the
> > > plate.
> > >
> > > Dave Goodfellow
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> >
> >
>
>
>
>
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