# Delta wound RPC Idler question



## Plum Creek (Dec 12, 2014)

After have some self induced issues with my VFD its time to get started on a RPC. I would really like to have a 10hp idler but my largest 3ph motors are 3hp and with the exception of the bandsaw, I can't see using more that one machine at a time. 
I have a 5hp 3ph WEG inverter duty motor that I initially bought to use as a Rpc Idler motor. That was before I read the warnings about using a delta wound idler. The data plate shows that it is Delta/Delta at low voltage (220v).  
Should I look for another motor or try it and see if it works?  Its not going to be cheap I've been looking for a 220v 250-350UF oil filled start capacitor for a few days now and not finding much under $100.


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## Ulma Doctor (Dec 12, 2014)

Hey Plum,
you wont need a oil filled start cap, the Start cap ideally is only left in circuit for a matter of seconds.
then it is taken out of circuit by either a timer or momentary switch
You might even want to rate the cap for 377V as an extra precaution for longevity. the cap wont actually deliver 377 volts it just has the capacity to work with 377.
you'd want oil filled caps for run capacitors due to the heat generated from their continuous use in the circuit.
a start cap shouldn't even get warm if utilized correctly.
i have not used a delta wound RPC, i imagine the idea should work in principle
a Delta Motor is gonna pull a few more amps on start up
it would be an interesting experiment, i will say that.

IMHO, id try to find a used 3 phase motor on Craigslist or an industrial surplus site if i were not up for experimentation. If you need a working RPC pronto, experimenting may not be the best road to travel.
it will be interesting to see how this develops
keep us informed!!!
good luck
mike)


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## John Hasler (Dec 12, 2014)

Consider using a single-phase pony motor to start the RPC.  1/2 HP should suffice.

Do you have a link to the warnings about using a delta connected motor for an RPC?


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## Plum Creek (Dec 12, 2014)

I havent ruled out a pony start but need to make sure that the RPC depowers after power failure.
I will see if I can find that post again when I get back home.


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## Chiptosser (Dec 12, 2014)

There is a lot of good information on RFC's and an other option a Phazpak.com
They have been at the game for 50 yrs.
The site is set up a bit different, but poke around, you'll find what you need.  

Good Luck)


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## Plum Creek (Feb 17, 2015)

I looked at the cost of buying the individual components the time required for assembly and decided to buy a prewired panel for my motor.  $125 shipped was about what the components would've cost me. 
Thanks to Ulma Doctor its all wired in and running normally. Thanks Mike!  In this case the Delta Delta configuration didn't seem  matter.  
I never did find the thread that I was on, that had indicated an issue with the Delta Delta configuration.


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