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Rockwell Carbide grinder voltage mystery

M. Moore

Titanium
Joined
Jun 8, 2007
Location
Vancouver Island, B.C. Canada
Here is a photo of the wiring in this grinder. It is a model 23-501.
The tag is long gone but there are three wires plus ground so it seems like a three phase motor but I have no idea of the voltage.
Is there a way to determine what the voltage is on a mystery motor?

Thanks in advance for any help....

Michael
 

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Yes, sorry about the pic, the automatic upload changes the resolution. Not much I can do about that.
It was a good clear photo on my iPad.
What am I looking for in regards to the resistance value?
 
A three phase motor is going to have three identical (or very close) resistances between terminals.

For a split phase cap start, cap start/run, or resistance start motor, you would expect to have two windings in series, one higher resistance than the other.

For a permanent split motor, you would expect two windings in series, either the same resistance or with some difference.

Are there any markings? It looks like there might be a nameplate on the top.
 
The nameplate that is important is missing. The nameplate still there has the model and serial number.
It seems the 23-501 model was either single or three phase.
I will check the resistance tomorrow and report the findings.
How does that tell me what the proper voltage should be for this motor?
I am pretty sure it is three phase but need to know the voltage.
 
I am pretty sure it is three phase but need to know the voltage.

If it has either 12 or (more likely) nine leads, it is a three phase motor. The vast majority of three phase motors are capable of running on either 208-240 volts or 480 volts, it just depends on how you wire the windings of the motor (series or parallel). Are the leads numbered? If so, what are they?
 
A lot of 3Ø motors Rockwell used had only 3 leads if 200V, or 208V, Rockwell used 200V long before NEMA made it the rated voltage for use w/ 208V, if 9 or 12 lead it is either a 220/440V or 230/460V motor, which one would depend on the age of the machine.


While this is not a question asked, here is a link to Delta serial numbers, to get a idea of the age of a Rockwell/Delta machine.

The Delta Vintage Project - Part One: Serial Numbers - VintageMachinery.org Knowledge Base (Wiki)
 








 
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