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Rewinding BIG transformer



Original poster: "Jason Johnson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <hvjjohnson13-at-hotmail-dot-com>

Hello,
 
Yesterday I got back from a state surplus auction that had equipment from
around lower Michigan. I managed to score a huge transformer for cheap (50
bucks!) there too. The transformer as it sits is good for stepping 2400 delta
down to 480 delta at 112.5 KVA (no thats not a typo). This thing is huge! It
weighs in at 950 lbs (we had fun getting it off the truck, my back is still
sore!) and is the size of a small refrigerator! It has a core area of about 25
inches^2 and is the standard EI core type, only the core is about 2 feet long
and 2 feet tall. 
 
What I was wondering was if I could rewind this beast for about 30kv at 24 KVA.
The only thing is I want to do this as cheaply as possible (read: as few turns
as possible). Solving the equation:
 
 A=74*PV/(f*PT) 
where:
A= cross sectional area of the core in square inches
74= guesstimated permeability of the core material (has worked well for all the
transformers I have)
PV= Primary voltage
f= frequency
PT= Primary turns
 
for PT:
 
PT=74*PV/(A*f)
And putting 240 in for PV, 25 for A, and 60 in for f; I get 11.84 for PT.
Is this right? Only 12 turns for 24KVA? Are my calculations screwed up? By this
same number I would only need 1500 turns for the secondary! I like these
numbers, but I'm afraid that they're not right!
 
Comments?
Jason Johnson