Re: widespread misconception (pig kVA)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>" <presence-at-churchofinformationwarfare-dot-org>

The rating according to the GE Distribution Transformer Manual (pub #
GET-2485R) is based of how much heat the tranformer can dissipate and still
not have spots exceed the insulation rating. Utilities know the daily usage
load is not symmetric and there are peak hours of power draw. Their
equipment is designed to handle this.

Once chart shows that 200% rated current is ok at 2000 seconds or less.
Another chart says that oil cooled tranformers can withstand 2.26 the rated
VA for 1 hour at 20C and 2.12 the rated VA for 1 hour at 30C assuming the
peak load does not exceed the rated VA for more than 50% of the time. There
is also data stating that 2.52 times rated VA is ok for one hour at 0C. This
makes it clear that distribution transformers are not made of fuse wire, and
heat is their enemy.

Contact me off-list for more details and the math behind these calculations.

KEN

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, October 07, 2001 12:54 PM
Subject: widespread misconception (pig kVA)


> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Pyrotrons-at-aol-dot-com>
>
> Hi All.
>
> I think there is some misconception dealing with pig ratings.
>
> I see a lot of pig powered Tesla coils on the web, in which their builders
> state something like "I'm running XXX amount of kVA into my coil, and my
pig
> is only rated half of that! Sometimes, the builder is a little surprised
that
> the pig is not killed due to pulling much more juice out of it than it is
> "rated".
>
> The faceplate rating of a pig, in kVA, is definately NOT the power that it
> can handle. I mean, the pig feeding 225A -at- 240V into most houses is rated
> 10kVA....................
>
> It must be the dissipative power rating. How much (I^2) R loss the pig can
> dissipate as raw heat. Or something, I don't know. But it can't be its
rated
> input/output power, no way, 225 * 240 is so far from10kVA.
>
> My main point is, you're not overdriving a pig until you're pulling
upwards
> of 225 amps from the primary. A pig CAN be overdriven
voltage-wise......Aron
> and I have done this a million times, putting 240V on the 120V terminals.
> This causes the core to saturate, but since it's externally current
limited,
> this is okay. Although we can actually hear corona on the inside it hasn't
> hurt anything. They're dang near indestructible. Notice I said dang
> near.....I'd like to shake the guy's hand who has killed a pig with his
Tesla
> coil ; ) I heard it has been done.
>
> My 2 * (10^-18) attocents on pig rating ; )
>
> Justin Hays
> KC5PNP
> G-3 #1150
> Email: pyrotrons-at-aol-dot-com
> Website: www.hvguy-dot-com
>
>
>
>