Hey electric motor experts, give me an opinion on this motor I scored today, please.

[GrizzlyBear]

Hey guys. I was able to snag an electric motor from an on-car brake lathe we were scrapping today. It's barely used and extremely quiet. Here's the specs on it from the plate:

Leroy Somer
003696
Model: #LS71C

I have no idea what some of the following stuff stands for, but I'll list it and its engraved value:

min -1: 3600
kW: .55
Cos: 0.8
A: 9
V: 115
Hz: 60

I would assume it's 3600RPM @ 0.55kW output. Which, from what I can tell converting kW to HP, is around 0.75HP.

Could this be a good motor to use in grinder build? It was free, after all

 

[Daniel Rohde]

Is it a very old style of motor? does it look enclosed(so grime and dirt can't get in)?

I would say yes. but it would be a little week for a 2x72

nice score though(if you don't find a use for it I'll take it)

Daniel

 

[Nathan the Machinist]

Fine for a disk grinder. Weak for a belt grinder.

I figure 2 HP and 1750 RPM is about right for a belt grinder.

 

[timgunn1962]

Looks like a 71-frame IEC Metric motor. It will almost certainly be TEFC. If it's a foot-mount, the frame size (71mm in this case) is the height to the shaft centre above the flat surface the feet stand on.

http://www.baldor.com/pdf/501_catalog/backcover.pdf

You seem to have the rest: .55 kW is .75 HP, 3600 RPM (though I'd have expected something a little lower to allow for slip at rated power; maybe 3400 RPM?), Cos Phi is the Power Factor and does not really matter to us on single-phase motors. 115V, 60 Hz.

9A seems very high. Are you sure it's not 4.9A?

 

[GrizzlyBear]

Thanks guys.

Ill get a shot of the specs plate and the motor and post them up later today.

Nathan, is 2HP really required for someone just starting in stock removal? I see several guys putting out nice blades using a Craftsman 2x42 and its only 1/3HP. I know higher HP would be ideal for really hogging off metal.

 

[C_Becker]

min -1: 3600 max revolutions per minute
kW: .55 power output in kW
Cos: 0.8 I guess it means cos Phi = effectivity factor, so you'd need 828W input for your 550W output.
A: 9 max current in Ampere
V: 115 operating voltage, in Volts (duh)
Hz: 60 mains frequency 60Hz

I would assume it's 3600RPM @ 0.55kW output. Which, from what I can tell converting kW to HP, is around 0.75HP.
Correct. kW x 1.36 = HP

Could this be a good motor to use in grinder build? It was free, after all

My text in red
80% effectivity is not that great for an electrical motor, but hey, it was free right

 

[BryanNomad]

I started on a 3/4hp rigged up harbor freight 4x36" grinder. I can tell you I got frustrated with it quickly, but I was doing 1/4" 5160 that wasn't descaled. My wife bought me a KMG for our anniversary and needless to say, it was a night and day difference. I'm spoiled I guess

 

[Ken H>]

A 1hp motor will work just fine in a 2X72 "IF" you're using a belt drive and not a VFD. Using a belt drive, use pulley combination to give something less than 2,000 SFM and you'll be just fine. I'd like at least 2 speeds to give lower speed around 1,000 SFM, and high of 2,000 SFM. Understand, a 36 grit running at 4,000 SFM will really hog some metal, but for a first timer learning on a 2X72, I think 2,000 SFM will work just fine for profiling. I do most of my beveling and finish grinding down around 1200 SFM.

Even a 3/4 hp (if scored for free, or very low cost) would be a decent start for a motor. Always change it out later.

Ken H>

Ken H>

 

[Stacy E. Apelt - Bladesmith]

Ken is giving good advice. Too much speed is more of a problem for new makers than power. A two of three speed multi-pulley setup with lower speed choices will make many learning steps better.

 

[GrizzlyBear]

Thanks again guys, always glad to get good advice and knowledge!

Here are a couple shots; one of the actual plate on my motor and another of a very similar motor mounted to the brake lathe (so you can see the case style).