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Rpc simple design unbalanced

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Rev. Mike

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Hello Mike
If I would build this exact setup what size would the fuse's need to be and the Amp for the coil need to be? I guess I need to let you know my motor is 208 V as well as you said this was for. Thanks
 

Ulma Doctor

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the motor fuses would depend on the hp rating of the motor
but as a rule of thumb is fusing is about 10 amps per hp
the control fuses are 1 amp
 

rwm

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Basic question: I don't understand how this is "rotary"? It looks like you box starts and runs 3 phase motors with no moving parts? What is the idler motor?
Robert
 

Ulma Doctor

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Basic question: I don't understand how this is "rotary"? It looks like you box starts and runs 3 phase motors with no moving parts? What is the idler motor?
Robert
Hi Robert,
technically it is a static converter, but few would understand the difference.
the rotary part comes when you couple the starting box, with an idler motor.
when the idler motor is running, it provides the 3rd leg of power that is lacking in most residential service
this 3rd leg, in conjunction with the 2 power company supplied legs, can be used to run 3 phase motors

my stater box, just gets the 3 phase motor spinning, quickly :grin:
 

Rev. Mike

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10 amp fuses would suffice, for the motor fuses
Would this Contactor "AC Contactor AC220V Coil 12A 3 Pole Phase NO Normal Open +1 NO Switch CJX2-D1210" work for a 208 V 1/3 hp 3 ph motor to make this setup and with his setup do I still need a idler motor also? Thanks
 

Ulma Doctor

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Would this Contactor "AC Contactor AC220V Coil 12A 3 Pole Phase NO Normal Open +1 NO Switch CJX2-D1210" work for a 208 V 1/3 hp 3 ph motor to make this setup and with his setup do I still need a idler motor also? Thanks
You can start a 3 phase motor with this set up.
An idler motor would increase the potential of the 3 phase circuit.
Without an idler you lose a portion of the motors hp rating
 

markba633csi

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I think it would be good to point out that a static phase converter and a rotary phase converter are both methods of running 3-phase equipment (motors) from a single phase power line. The static method usually allows only about 2/3 horsepower with any given motor load. In other words, a 1 hp motor running on a static phase converter will only deliver about 2/3 horsepower.
The rotary phase converter is more efficient but of course it is more expensive.
mark
 

tjmlack

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Hi Mike,
Would you tell me where you bought the momentary start button (DPST switch) with both contacts NO that you show in your wiring schematic?
Thanks,
Tony
 

Ulma Doctor

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Hi Mike,
Would you tell me where you bought the momentary start button (DPST switch) with both contacts NO that you show in your wiring schematic?
Thanks,
Tony
i got the square d NO contact blocks on ebay and assembled the switch
 
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