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VFD 5 wire motor

Posted: Fri Apr 16, 2021 10:36 pm
by DRS
I am doing a conversion to Acorn and Clearpath NEMA34 servos. Everything is working great on the axis drives but I am hung up trying to figure out the spindle motor. It is a 3 phase AC motor on a Journeyman 425. I have wired many 3 wire 3 phase motors in the shop thru the years but only now encountered a motor with 2 additional wires. The extra wires are a size smaller and have a resistance reading of about 350 ohms. I am at the point of wiring the VFD to the motor but don't know what to do with the extra wires. There are no plates or nomenclature on the motor housing. Any help would be appreciated.

Re: VFD 5 wire motor

Posted: Fri Apr 16, 2021 11:05 pm
by tblough
My guess is they are thermostat wires and can be left unconnected. Insulate them just to be sure.

Re: VFD 5 wire motor

Posted: Sat Apr 17, 2021 8:44 am
by DRS
Thanks for the reply. What do you think about the possibility it is electrically excited synchronous type? The second illustration in the video shows a 3 phase motor with 3 +2 wires. The 2 smaller wires may be for DC stator current?

Re: VFD 5 wire motor

Posted: Sat Apr 17, 2021 8:45 am
by tblough
Could be. Without a manufacture and model you are just guessing.

Re: VFD 5 wire motor

Posted: Sun Apr 18, 2021 10:08 am
by martyscncgarage
tblough wrote: Sat Apr 17, 2021 8:45 am Could be. Without a manufacture and model you are just guessing.
EXACTLY! We can not "SEE" what you "SEE"
Take the time to post a picture of the nameplate of the motor.

Marty