[Prev][Next][Index][Thread]

Re: More Tuning/Debugging

Tesla List wrote:
> 
> >From bert.hickman-at-aquila-dot-comSun Sep 15 21:29:38 1996
> Date: Sun, 15 Sep 1996 09:40:34 -0700
> From: Bert Hickman <bert.hickman-at-aquila-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: More Tuning/Debugging
> 
<SNIP>
> > enough that the idle current at the rated voltage is not noticeable
> > in my controls. Space is not really a problem, I have a sturdy engine
> > cart that will carry two cans and rolls around easily enough. Total
> > weight will be 750 pounds.
> >
> > Soooo. A good chunk of my check, not to mention my August bonus, went
> > out in the mail earlier today...
> >
> > Richard Quick
> >
> > ... If all else fails... Throw another megavolt across it!
> > ___ Blue Wave/QWK v2.12
> 
> Congrats on the pending new addition to your family of pigs! You also
> still have your 23 KV beast don't you?  Your last post brought up an
<SNIP>
> When I was talking with the folks at Solomon, I was originally looking
> at getting two 5 KVA transformers, foolishly thinking that each would be
> smaller and easier to move rather than a single 10 KVA beast. They
> informed me that there was very little difference in physical size or
> weight between the two sizes, and that 10's were more readily available.
> As a result, I opted for a single 2-bushing pig, which was about 50 lbs
> heavier than their 10 KVA 14.4 KV pig. In listenning to your description
> of the 25 KVA pig, I'm beginning to wonder if Solomon may have
> "underrated" the KVA of my refurbished pig - I asked for a 10 KVA and
> they sent me one with a big "10" painted on the case. Since I had to
> wait a while, they may have custom wound the "primary" to provide the
> 19.9 KV output. But it weighs about the same as your 25 KVA animal -
> could this be added weight of insulation(?). I've also heard in a
> previous post by someone that 10 KVA's are basically "throw aways" in
> the distribution transformer business.
> 
> I sure would think that a 25 KVA transformer would have MUCH more iron
> in it than a 10 KVA. I also would also have thought a 75 KVA transformer
> would be in a significantly larger case (maybe even with fins) than the
> one I have. It now makes me wonder if I should have spec'ed a larger KVA
> rating since it seems that the cost, size, and weight is about the same,
> and TC performance MAY be more stable. Maybe I really have a 25 in
> disguise(?)!
> 
> Any pig experts out there that can shed light on this?? Inquiring minds
> want to know! :^)
> 
> -- Bert --


Bert,

The main difference in different KVA pigs is the iron and size of wire 
(almost 100% aluminum now).  The same can can often house from 10-75KVA. 
 It depends on the service the unit is put in.  I have seen some 100KVA 
pigs that are 7 feet tall and 3 feet in diameter.  Two blocks from my 
home, on a single pole, are three clustered 333KVA units about 3.5 feet 
in diameter and no taller than a big 10KVA pig!  Go figure!  I would opt 
for two large sized 5 KVA single bushing 7600 volt pigs if I were 
searching of the ideal setup for Tesla work.  Too many KVAs mean higher 
magnetization current (wasted power) and demand a much stiffer 
controller.  I would check my pole pig feeding my home and use something 
1/5th as big for Tesla work.


Richard Hull, TCBOR