[AMPS] HV Pole Pigs ++

[Steve Katz]

> Well the pole pigs I have aren't that big.  Mine are all either 5 or 10 
> KVA, perhaps the occasional 3 KVA unit.  But these are disappearing 
> quickly.  With upgrades to the distribution system around here during the 
> past few years, 25 KVA is pretty much the smallest size they're putting a 
> pole now. And those are with 16 KV primaries.
	[Steve Katz]  I've never even seen any that small.  The pole pig
mounted directly behind my home is 96kVA and is quite small (exterior).  The
local utility company, Los Angeles Dept. of Water and Power (DWP) tells me
even these are obsolete, current stock is larger, typically 600A x 240V =
144kVA, that's to supply four residential homes.  I don't know what they'd
do with a 3-5-10kVA unit, that would barely supply my electric cooktop,
which is 240V @ 40A = 9.6kVA, and just one appliance.  I can hold a 3kVA
transformer, a la the one in the Alpha 87A, in the palm of my hand.
-WB2WIK/6



> Phl
> 
> At 04:13 PM 12/20/2001 -0800, Steve Katz wrote:
> 
> >I'm still trying to figure why hams (including me, in my younger and
> >stupider days) feel the need to use a 96 kVA transformer to power an
> amateur
> >amplifier.  Even tubes with really big handles don't need a 96 kVA
> source,
> >but that's what the average pole pig is.
> >
> >-WB2WIK/6
> >
> >"Each success only buys an admission ticket to a more difficult problem."
> --
> >Henry Kissinger
> >
> > > -----Original Message-----
> > > From: Phil (VA3UX) [SMTP:phil@vaxxine.com]
> > > Sent: Thursday, December 20, 2001 2:54 PM
> > > To:   amps@contesting.com
> > > Subject:      Re: [AMPS] HV Pole Pigs ++
> > >
> > >
> > > Not a bad point Jack.  Ultimately most of the pigs are removed from
> the
> > > can
> > > when used for amateur service. I don't know about the standards in the
> US
> > > but here in Canada, these pole transformers had to have enough sheet
> > > insulation between winding layers to meet the electrical requirements
> > > *before* they were put in oil.  The oil then just added a huge
> additional
> > > insulation factor as well as providing the required cooling. This came
> > > from
> > > a conversation I had with a design engineer at Ferranti-Packard (at
> one
> > > time, one of the largest makers of pole transformers in Canada). So at
> > > least in Canada, these things can be safely run dry.  However the
> sheet
> > > insulation is still subject to the same time/temperature/aging effects
> as
> > > any other transformer so eventual failure is expected.
> > >
> > > Phil
> > >
> > > At 12:50 PM 12/20/2001 -0500, you wrote:
> > >
> > > >One thing to remember..........the oil that these transformers
> normally
> > > >operate in is not just for cooling, it is for insulation!
> > > >The oil has good dielectric properties.  I used a pole pig for some
> time
> > > and
> > > >it ultimately failed after it arced internally to the core.  I had
> > > removed
> > > >it from the can and allowed the oil to drain off.  Probably a good
> idea
> > > to
> > > >leave the transformer in the can and keep it in oil to avoid such
> > > problems.
> > > >Unfortunately, that makes for a rather large unit!
> > > >73,
> > > >Jack, W9GT
> > > >----- Original Message -----
> > > >From: "Geo Clute W7LFD" <gclute@attbi.com>
> > > >To: <amps@contesting.com>
> > > >Sent: Thursday, December 20, 2001 12:39 PM
> > > >Subject: RE: [AMPS] HV Pole Pigs ++
> > > >
> > > >
> > > > >
> > > > >
> > > > > I like the concept of "Dial-A-Voltage".  Variac and pole peg
> mounted
> > > > > in a 4 wheeled photo copier cabinet.  Oh yes...an Edsel steering
> wheel
> > > > > on the Variac.
> > > > >
> > > > > Still looking for the Edsel.
> > > > >
> > > > > Geo W7LFD
> > > > >
> > > > >
> > > > > --
> > > > > FAQ on WWW:               http://www.contesting.com/FAQ/amps
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> > > > >
> > > >
> > > >
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> > >
> > > --
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> 

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