Re: Getting more input power

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

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

Your local practice may vary, but...
In the US, a X Amp feed means that all the phase conductors each can supply
X amps.  For a 240/120, that means two wires at X amps (out of phase..of
course)... For 3 phase, each leg can carry X amps.

Watts wise, that means that a X amp, 240V 3 phase service can supply
X*240*3/1.76 watts.  (The 1.76 is because the voltage is between the
legs(delta), but for power, you have use the Wye/Star voltage)

In your case, I would imagine that the 50Amps is on each leg.

You cannot hook up a 240VAC NST between the legs to get 415V in.. The NST
will saturate and overheat.

What you can do is use multiple NSTs, one on each leg (Star/Wye connection),
and combine the outputs with HV rectifiers to make a DC source.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, January 02, 2004 7:56 PM
Subject: Getting more input power


 > Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au>
 >
 > Hi all,
 >
 > I have been talking to my electrician about getting a 50A feed into my
 > workshop.
 > He has informed me that this is usually done with a 3-phase connection.  I
 > should have pressed him for some more questions, but forgot, so I'll ask
the
 > knowledgeable people on this list.
 >
 > My knowledge of 3-phase power is sketchy, whilst I do understand the
basics.
 >
 > If the outlet is rated at 50A 3-ph, then how much power is available per
 > phase (to neutral) ?
 >
 > If it is 1/3 of 50A that is OK, I could split the power - use one phase
for
 > the HV supply, and another for the RSG - but this raises a major issue.
The
 > RSG will be out of phase with the HV supply by 120 or 240 degrees
depending
 > on which two phases I use.  Is there any way of adjusting this with some
 > sort of phase angle adjustment.  The JF phase adjuster can only manage
about
 > 90 degrees or so I believe.
 >
 > I wonder how my NST's would cope if I connected them between phases ?
This
 > way they would be getting 415VAC, not 240VAC - and I wonder if the
 > insulation in the tranformers could cope with the higher voltage.  Anyone
 > tried this ?  My guess is .. no way .. we would be upping a 15kV
tranformer
 > to nearly 30kV, and we all know this is about the dialectric strength of
 > air, and the first real problem point for insulation breakdown and corona.
 >
 > Rgs
 > Ian
 >
 >