Re: [Amps] single phase into 3 phase transformer

["Fuqua, William L." <wlfuqu00@uky.edu>]

It would seem that if you short out the center coil there would be a better 
balance between the remaining two in case you need to parallel the two 
primaries.
  As I said these are multi-kW transformers 10 to 25 kW with eye-bolts on some. 
I don't need full capacity of the transformers. The cheap static converters 
simply run motors mostly on single phase and a capacitor in series on the third 
to provide some starting torque in the right direction. These will not work on 
3-phase transformers in DC power supplies.
   I have seen the shorting of windings on one phase, which is counter 
intuitive, but the physics works just fine.
The only other issue is filtering. More capacitance would be needed.
73
Bill wa4lav
________________________________
From: Amps <amps-bounces@contesting.com> on behalf of Doug Ronald 
<doug@dougronald.com>
Sent: Wednesday, April 21, 2021 1:29 PM
To: amps@contesting.com <amps@contesting.com>
Subject: Re: [Amps] single phase into 3 phase transformer

CAUTION: External Sender


Simply short-out all the windings on one leg, probably one of the outside
legs to keep the flux path shorter. Then the two legs left will get all the
flux and behave like a single-phase transformer. Phase the two windings
remaining remembering that the flux circulates in a loop around the
remaining legs.

I have done this with my power distribution system and have found very low
loss in the now single-phase transformers.
73, Doug, W6DSR

-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Fuqua, William
L.
Sent: Wednesday, April 21, 2021 00:47
To: amps@contesting.com
Subject: [Amps] single phase into 3 phase transformer

What is the preferred method to wire a 3 phase transformer to operate off of
single phase?
I have heard of several possibilities and happen to have a mess of multi kW
three phase HV transformers.

73
Bill wa4lav
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