10 HP rotary phase converter issues

Esmith41

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Hello everyone, first post. I built a rotary phase converter and all seems well except when the converter is started up the 10 hp motor shaft locks up I can’t turn it by hand until I turn off the converter. I tried moving the 3 phase wires around on the motor leads with no luck. I wired the motor for low voltage per the attached diagram.73A0F858-B804-4407-8B97-D9CBBC8B5CCD.jpeg1AE501F1-A6F3-451B-B061-2C0A15A10AEE.jpeg27DFBCD8-A4E7-4399-8E84-EF68478F2A22.jpeg50E982E0-4292-4CB8-9096-AB3C474CDBBA.jpeg
I have not been able to balance the voltage yet due to the motor not generating the 3rd leg. The motor is brand new out of the crate ( see photos) 60 amp breaker at supply panel.
Any help will be greatly appreciated.
 
If it's humming loudly when it locks up then something must be mis-wired I would think- check your connections again- does the motor spin freely
when powered off? No problem with bearings? I'm also wondering if maybe you don't have enough starter cap?
Mark
 
Alls not well if it locks up, sounds like the rpc motor to me. , Ied vfd it if doable
 
The start capacitor is around 500 micro ferands. Just to be clear this is the “pony” motor used to generate the three phase power that I am having trouble with. It spins freely when not energized. I will look at the motor wiring again.
 
Think your start capacitor is too small. Try a 750-850 mfd 400 volt. Usually a good rule of thumb is 75+ mfd per horsepower.
 
I'm having a little trouble following your wiring in the panel, could you provide a drawing of the circuit?
 
Here you go. I am by no means an electrician or electrical engineer but here are “my schematics”. Probably not much better than the picture of the RPC.90D89C36-195B-4B77-8499-6C680127D1BD.jpeg
 
I'm not 100% sure but I think your pushbutton might be miswired-
 
The attached PDF might help you. As @markba633csi said, I think the double throw switch is wired incorrectly. In the attached file, you can ignore the control power transformer and use full voltage coils in the contactors. The main idea is to temporarily connect the start cap between one of the input legs and the manufactured leg. Cpf in the drawing is not required, but does make the system more efficient.
 

Attachments

  • FitchWConverter (1).pdf
    2.1 MB · Views: 11
I highlighted the circuit for the start capacitor. I think I have it wired correctly. The only thing I see I could do differently is move the the supply power for the capacitor from the load side of the contactor to the line side. This would give power to the capacitor before switch is pushed and the contactor is pulled in. I have of the the momentary switch throws filed down so the capacitor is energized a split second after the contactor is energized.
Thanks for your suggestions everyone, Just talking about it and getting a different set of eyes on it make me think a little different and hopefully gets me closer to a solution.
Eric
 

Attachments

  • RPC schematic mark up.pdf
    54.3 KB · Views: 16
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