Subject: Re: [Amps] 3 phase transformers on single phase - advice pls?
Dave,
If you parallel two of the three primary windings fed with 240V single
phase, and series the two corresponding secondary windings, I believe you
would get about 4376V, 8kVA (4kVA per coil). This assumes two primary legs
are actually 180 degrees out of phase.
Jim Smith,
KQ6UV
That is correct, Jim.
I have converted many (23) Henry 2000D (3CX3000A7) RF Generators using this
method
very successfully.
The center winding on the HV transformer has no connections to it; primary nor
secondary. The 240 volt mains connection is to the 2 outside windings; in
parallel. The jumper between primary connections must be connected so that the 2
primary windings are not bucking each other. If connected backwards, there will
be
no output from the secondarys. The center secondary output wire is taped off,
and
unused. If the filter is choke input, you remove the choke, increase the filter
C
to 50 mfd or so, and increase the bleeder resistance to 200k ohms or so. You
need
to fabricate a step-start circuit for the primary side of the HV transformer.
This
converts the filter to C input, and you actually gain a few hundred volts over
the
original choke input system. Fortunately, Henry uses 120 volt filament
transformer, control circuits, and blowers, so no further changes are necessary.
YMMV on your conversion, depending on the circuit.
(((73)))
Phil, K5PC
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