Correct Greast to Lubricate Electric Motor Rear Bearing?

robfish · Post by **robfish** » Fri Jul 13, 2012 11:54 am

Disassembling my electrical motor, moving the rubber boot of the centrifugal switch's electrical contacts, and blowing compressed air into the switch made the motor stop groaning and start purring along.

Unfortunately, the process also coated the electric motor's rear bearing with sawdust (if I ever do this again, I'm going to try and remember to cover the bearing with plastic before I pull out the compressed air).

When I wiped off the sawdust, I also removed the grease that was on the outside of the bearing. Because of the amount of grease that was there, I'm feeling like I should push some more grease into the rear bearing assembly.

The question is, what kind of grease?

Any suggestions?

The electric motor is 1 - 1/8 HP, 115V, 3450 RPM made by GE.

Thanks!

dusty · Post by **dusty** » Fri Jul 13, 2012 11:58 am

With the motor torn down, I would not bother with grease. I would put in a new bearing. Note however that I say this with no experience on this particular motor type. I would do that just because "I would".

robfish · Post by **robfish** » Fri Jul 13, 2012 12:13 pm

dusty wrote:W... I would not bother with grease. I would put in a new bearing...

Installing a new bearing is a great idea... though I suspect I'll still need to lubricate the bearing with some sort of grease.

For what its worth, the name plate on the electric motor says for other service besides lubrication I should see "GEI-56110." A search of the internet for GEI 56110 turned up a bunch of results that said "see GEI-56110," but I didn't see any results that actually were the GEI-56110.

I found a GE Energy Industrial Solutions' Customer Service page that said to call 800-541-7191 for customer service on motors. I left a message in their voicemail system.

Guess I'll now try to find the part number and a source for that rear bearing.

wa2crk · Post by **wa2crk** » Fri Jul 13, 2012 12:28 pm

Every GE motor that I have seen from a SS contained a shield over the ball bearings. None of them had an open frame bearing. The grease that you have seen may be the liquid portion of the grease being leached out of the bearing due to the accumulated sawdust. I have replaced all of the bearings in the headstock with sealed bearings when I service a headstock. If I have to open any electric motor from a headstock I replace the bearings.as a routine matter. Why put the motor back together with a bearing that might be questionable?
Bill V
PS I have been getting bearings from VXB Bearings on the internet for several years and have not had any problems. They also have a bearing finder. You plug in the ID, OD and width of the bearing and it pops up the proper bearing and their stock number.Be cautious I have found that one of the motors that SS used has different bearings on each end of the shaft. one end has a standard bore and the other is a 5/8" bore so be sure to measure accurately before you order.
Bill

pennview · Post by **pennview** » Fri Jul 13, 2012 12:42 pm

Those motor bearings are sealed bearings and there don't need any lubrication/grease. If you found grease on the outside of the bearing, the seals likely are bad and you ought to replace them, especially since you have the motor apart. You really don't want any grease inside the motor collecting saw dust.

You should be able to read the bearing number on the side of the bearing. If not, you can measure them -- outside diameter, bore diameter, and width -- and get some to match or just take them to a bearing shop and they'll do the measuring.

JPG · Post by **JPG** » Fri Jul 13, 2012 1:37 pm

6203 2 RS 17 x 40 x 12 rubber sealed

wa2crk · Post by **wa2crk** » Fri Jul 13, 2012 3:14 pm

JPG
You are correct on the number but I have said that at least one of the motors uses different bearings. It uses the 17X40X12 mm on one end and a 5/8X40X12 on the other end but both bearings are numbered with the 6203 nomenclature. In fact VXB's part number for the bearing with the .625 bore is 6203-2RS-10 with the "10" indicating the 5/8 bore.
They do not interchange.
Bill V
PS I can't remember whether it was the GE or the Emerson which used the different bearing set.

robfish · Post by **robfish** » Fri Jul 13, 2012 3:21 pm

There was definitely grease on the back end of the bearing, and enough grease accumulated in the back cover of the electric motor that I have a hard time seeing how it could have leaked out of the bearings.

There are two metal "rings" sitting in the grease in back cover of the electric motor. The first time I took the electric motor apart, one of those "rings" stuck to the bearing. Since then, the "rings" have been staying in the back cover when I've taken the cover off.

I've attached photos of the bearing and the back cover. The side of the bearing shown was pretty much coated with grease when I first opened the motor. I wiped the grease off before testing the motor so I wouldn't have a ton of sawdust running through the bearings.

dusty · Post by **dusty** » Fri Jul 13, 2012 3:34 pm

robfish wrote:There was definitely grease on the back end of the bearing, and enough grease accumulated in the back cover of the electric motor that I have a hard time seeing how it could have leaked out of the bearings.

There are two metal "rings" sitting in the grease in back cover of the electric motor. The first time I took the electric motor apart, one of those "rings" stuck to the bearing. Since then, the "rings" have been staying in the back cover when I've taken the cover off.

I've attached photos of the bearing and the back cover. The side of the bearing shown was pretty much coated with grease when I first opened the motor. I wiped the grease off before testing the motor so I wouldn't have a ton of sawdust running through the bearings.

That does not look right. It does not even look like what I would expect motor bearing grease to look like. I know that I would change bearings after seeing that.

Bill, Bill Mayo where are you. We need you, Man.

pennview · Post by **pennview** » Fri Jul 13, 2012 5:27 pm

Perhaps the previous owner though adding a bit of grease was a good thing.

It could be, or perhaps the motor actually uses two 6203 2 RS bearings, but the prudent thing to do is pull them and verify what's there before getting replacements.