Phoenix Phase Converter Question

Hi All
I have a Bridgeport V2XT milling machine being fed by a Phoenix 10 hp RPC, the milling machine is operating eractily and part of the troubleshooting process is to check various voltages.

L1 to L2 241 volts
L2 to L3 251 volts
L3 to L1 257 volts

L1 to Ground 120 volts
L2 to Ground 120 volts
L3 to Ground 228 volts

These readings were taken inside the milling machine electrical box. The milling machine has two transformers (T1 and T2) that feed various electronic controls and a 3 phase spindle motor . The milling machine is wired so the spindle motor gets L1,L2 and L3 and each transformer gets two legs. So T1 is fed from L1 and L2 and T2 is fed from T2 and T3. So the question is is the phase to phase balance out of spec and why is the L3 to ground so far out. Any advice ???

I Assume L1-L2 are the 240v single phase supply to the RPC, these are carried through to the 3ph termination to provide two of the phases.
The readings to ground are normal and are meaningless, but any 1ph control transformer or supply fed from Anything but the two 240v 1ph input conductors can/will cause problems.
Al.

I now see what you are talking about. I wonder if I could put both transformers on L1 and L2 , is there any downside to wiring it that way? I don't want to let any smoke out of the wires !!!!!

If the transformers offer complete isolation I don't see why you could not?
Ensure that the source of the 240v 1ph (L1-L2) have adequate protection/fusing, wire size etc.
Usually the only reason on the original equipment was to balance the 3 phases.
Al.

1.What do you mean by isolation? 2. I will review the fuses,wire size etc and I agree with what you say about being balanced 3. I have had another crazy idea as well. What do you think if I just plugged the transformers directly into the 240Vac and arrange it so the spindle motor was wired to the Rotary Phase Converter. As I understand the wiring diagram the transformers are using 240ac any how and the control for the spindle motor is 24vdc. Thanks for the advice.

That is what I meant to place all the single phase transformers across the main L1-L2 240v (1ph) supply pair.
Al.

you are having better luck then me but after contacting Phoenix I found out they have CNC balanced unite. PS don't do digital on a CNC .

Quote:

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Originally Posted by sansushi

you are having better luck then me but after contacting Phoenix I found out they have CNC balanced unite. PS don't do digital on a CNC .

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What do you mean, Don't do Digital on a CNC

I meant stay away from static phase converters because when they fail it will burn up your motor .Phoenix is sending me a state of the art all new designed unite , when I get it next week ill let you know.Now they told me your voltage issue is normal and will work fine on a plane motor.