Re: How about this for a power supply

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

Original poster: "David Sharpe by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sccr4us-at-erols-dot-com>

It is similar to a pole pig.  I assume that the primary is 480V delta
(multitapped) and 
secondary is 'Y' connected.  If the assumption is correct, the secondary line
to ground 
phase voltages would be (9000)/sqrt(3)); or approximately 5.2kV.  This would
result in 
a secondary to primary turns ratio of (5200/480); or about 10.8:1.  You would
need to 
convert to single phase input (240), and output. 

If the primaries (A and C windings looking at outside windings) are connected
in parallel 
with additive phasing, and the 'B' phase is not connected or physically removed
from the 
transformer core, secondary voltages would add (x2) versus sqrt(3) multiplier. 
This would 
result in 240 Vin, and 10.4kV out.  Notice that dielectric stress is virtually
the same, and if 
the 'B' phase is removed, the actual dielectric stress on the transformer is
reduced. 
Also be aware that kVA reduction to 57% of nameplate (~5.1kVA) results, by
converting 
to single phase and eliminating the middle 'B' phase windings.  With short duty
cycle service, 
a transformer modified as above should be capable of above 10kVA under these
conditions. 
WARNING:  Performing this modification is dangerous without proper tools,
instruments 
and experience modifying transformers or working with HV,  this modification
requires 
a lot of work. 

I'm getting ready to convert a 240 delta : 3kV 3ph unit to 240 X 3.5kV single
phase via 
similar approach for a large research P-P  hartley oscillator VTTC.  Reply
off-line for 
additional info. 

Regards 
Dave Sharpe, TCBOR 
Chesterfield, VA. USA 

Tesla list wrote: 
>
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Kidd6488-at-aol-dot-com> 
>
> In a message dated 11/22/01 10:46:01 PM Eastern Standard Time,
> tesla-at-pupman-dot-com 
> writes: 
>
> > 
> >
> <<http://cgi.ebay-dot-com/aw-cgi/eBayISAPI.dll?ViewItem&item=1663422759>http:/
> /cgi.ebay-dot-com/aw-cgi/eBayISAPI.dll?ViewItem&item=1663422759>http://c 
> > gi.ebay-dot-com/aw-cgi/eBayISAPI.dll?ViewItem&item=1663422759 
> > 
> > Imagine how much of a hurting this could put on ya, BTW could someone 
> > tell me how to figure ###VA 
> > 
> > is this comparable to a pole pig

.