10 HP rotary phase converter issues

Your switch symbol is not clear, it looks like the contacts connect top to bottom? Tip: use standard schematic symbols
A la:
2psw1a.jpegMark
 
After looking at your drawing, I think I agree that it's wired correctly. If your switch is wired correctly it looks like it should start the motor when the switch connects the start cap to the circuit. I think the start cap needs to connect before the contactor closes, then disconnect when the motor is spun up.
 
I found a loose spade end on one of the connections at the start capacitor. I repaired the end and the motor spun instead of locking up. It would not get up to speed so I’m thinking it will need another 300 mfd start capacitor to get it up to speed on the start. It may be awhile before I can get to it but I will let you know how it turns out.
Thanks again for your help.
Eric
 
hey folks. A little update. After moving the start capacitor to the line side and making it so the the start capacitor engages before the contactor, the motor finally turned instead of locking up. Now that it was finally turning, the motor did not come up to speed. I added another 200 mfd start capacitor and this did not help either. I checked my voltage on the line side and the load side on start up and found the voltage droppping down to 175v. I am using 10 awg wire from a 60 amp breaker for approximately 6’. According to the voltage drop calculator I should be just fine, as it is only loading about .17% of the volts. Not being sure if upsizing the wire would work I hooked a 5 hp 3 phase motor and it ran perfect. I balanced the three lines and my Lathe is finally up and running. But, it still bothers me that the 10hp will not come up to speed. Do you think if I upsize the conductors to say, 8awg it will make a difference?
Thanks,
Eric finally going to make some chips for the first time Smith
 
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A few things to do.
First isolate the run capacitors while the motor is starting.
Second, the motor power contactor needs to be closed while spinning you the motor.
Start time should be 5 to 6 seconds max on a motor that small. If it's not coming up, something ain't right.


I would be curious about the current draw during startup when you are seeing 175 volts across the 240 line.
I would advise you to read my other RPC posts and then redesign accordingly.

From what I am seeing you are using a panel mount pushbutton switch to connect your start capacitor.
That is a disaster waiting to happen. Those switches are rated for 3 to 5 amps. 10HP 3 phase motor, being forced to start with a start cap and ont 3 phase power, the current draw is an easy 40 to 60 amps. The push button is just not designed for that. You need a 30 amp contactor or relay for that power level.
 
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