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Forum Index : Other Stuff : How many poles on this motor?

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philb

Regular Member

Joined: 05/07/2008
Location: United States
Posts: 96
 Posted: 09:03am 28 Dec 2008 Copy link to clipboard Print this post

I recently purchased 3 phase metal turning belt driven lathe. If I measured correctly, it is a 16" X 74". By the look of the castings, I'm guessing it was made in the 1940's or 50's. Everything seems to be in great shape.

It has no name plate anywhere on it to tell me who manufactured it. Best guess, it's an old Warner Swayse.

I purchased a Hitachi VFD drive to convert 240 split phase electricity to 3 phase. The instructions want to know how many poles the motor has. Does anyone know how to tell without taking it apart? Bryan 1 maybe?

Motor Specifications:
Lima Electric Motor Company
Lima, Ohio
Type R3
Frame 225X
Code 1

60 Hz
9.2 amps@220 volts
1200 RPM (has a gearbox mounted to the motor)
3 HP
3 phase
9 lead
star connected

Here's a few pictures of the beast.

philb

Dinges
Senior Member

Joined: 04/01/2008
Location: Albania
Posts: 510
 Posted: 09:30am 28 Dec 2008 Copy link to clipboard Print this post

Short answer:
You have a 6 pole motor.

Long answer (teach a man to fish, as opposed to giving him a fish...):

For your American 60Hz grid frequency, number of poles = 7200/RPM = 7200/1200 = 6

For us Europeans (or anywhere else that uses 50Hz grid power), number of poles = 6000/RPM

Keep in mind that for VFD duty it's best to use VFD-rated motors, as the sharp pulses of the VFD PWM put larger stresses on the insulation than the 'gentle' sines that come out of the grid. Judging by the nameplate that motor is a little older so likely not VFD rated. Personally I wouldn't have trouble using it with a VFD, but keep in mind that it may suffer from a reduced lifetime because of lack of proper rating. Still, it's early enough to shop for a new (VFD-rated) motor when the present one fails, I suppose.

Peter.

philb

Regular Member

Joined: 05/07/2008
Location: United States
Posts: 96
 Posted: 10:28am 28 Dec 2008 Copy link to clipboard Print this post

Thanks Peter.
I'm going to take a chance and may shorten it's already long lifetime. I have a 5 HP already waiting...if it doesn't morph into a wind turbine first.
philb

wdyasq

Newbie

Joined: 29/07/2008
Location: United States
Posts: 21
 Posted: 03:40pm 28 Dec 2008 Copy link to clipboard Print this post

Because of the Bushings rather than bearings (I think), I'd add some maturity to the age guess.

Ron
Adventure is just bad planning." -- Roald Amundsen

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