Correct Greast to Lubricate Electric Motor Rear Bearing?

[rjn2649]

To me it looks like someone had it apart, and packed it with grease. I just got done cleaning up a motor at work, someogoofball greased up like that. Those "rings" are probably just shims to remove end play and stop the shaft from whatever slight movement there may have been.

[robfish]

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

The previous owner was the Shopsmith Store in Columbus, Ohio. I bought the unit from them, brand new, in the late 1970's, and this is the first time the headstock has ever been taken apart.

I've never replaced a bearing on an electric motor - do I need some sort of bearing puller to remove it and/or a press to put the new one on?

[robfish]

If I'm going to be buying a new rear bearing, I'm guessing it would probably be a good idea to take the pulley assembly off the shaft and replace the front bearing too.

Is there anything else I should consider replacing/refurbishing while I've got the electric motor apart?

Thanks!

[wa2crk]

Blow out all of the dust and debris and clean the centrifugal switch contacts.
Bill V
PS;
I generally coat the OD of the bearing with a VERY LIGHT coating of lithium grease to ease the installation and prevent future corrosion.

[JPG]

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.

He stated he had a GE motor.

ALL the Mark 5...V motors use two 6203 bearings except the Emerson which uses a 6203-2RS-10 for the rear bearing(5/8" id, the rest is the same) and one like all the rest for the shaft end bearing.

i.e. the Emerson rear bearing is 5/8" id x 40mm od x 12mm wide.

I am sure the 'rings' are shims to limit end play- clean em up.

I would NOT grease new bearings.

[robfish]

I've been trading emails with a nice guy from an authorized GE electric motor distributor. I asked him about greasing the electric motor, and also whether or not I should remove the shims (which is what I believe the metal rings are).

Here's his reply:

The shims are probably fine,

I’d thoroughly clean the housing removing all the old grease, replace the bearing with a new one grease it up, drop in the and shims and re-grease part of the housing with new grease.

You won’t need much, so if you pick up a small tube at Grainger that’ll be more than enough.

Here is the recommendation from SKF.

Excessive amounts of grease will cause the operating temperature within the bearing to rise rapidly, particularly when running at high speeds. As a general rule, when starting up only the bearing should be completely filled, while the free space in the housing should be partly filled with grease. Before operating at full speed, the excess grease in the bearing must be enabled to settle or escape during a running-in period. At the end of the running-in period the operating temperature will drop considerably, indicating that the grease has been distributed in the bearing arrangement.

Since you’re not running this full time like a blower motor you need not worry too much about a run in period, but the principle of greasing the bearing and only half the housing area would apply.

All in all you’ll be fine, just get all the old stuff out and replace with fresh is cheap insurance.

So on one hand, most of the posts in this thread suggest I remove all the grease and do not add any when I install the new bearings.

On the other hand, my Shopsmith came from the factory with grease in the bearings, someone at GE's authorized distributor suggests adding grease, and at least one bearing manufacturer recommends adding grease.

Decisions, decisions, decisions. Ah, the joy of doing stuff that isn't in your area of expertise!

[JPG]

I've been trading emails with a nice guy from an authorized GE electric motor distributor. I asked him about greasing the electric motor, and also whether or not I should remove the shims (which is what I believe the metal rings are).

Here's his reply:



So on one hand, most of the posts in this thread suggest I remove all the grease and do not add any when I install the new bearings.

On the other hand, my Shopsmith came from the factory with grease in the bearings, someone at GE's authorized distributor suggests adding grease, and at least one bearing manufacturer recommends adding grease.

Decisions, decisions, decisions. Ah, the joy of doing stuff that isn't in your area of expertise!

Considering the source of your new info, I would proceed as suggested.

For myself, I 'assumed' the grease was 'leakage' from the original bearing.

Well I've learned my new thing for the day!:)

[pennview]

Something to ponder -- if the replacement bearings are sealed, and the seals are there to keep dust and other contaminants out, how would grease get through the seals to the bearings inside?

[JPG]

Something to ponder -- if the replacement bearings are sealed, and the seals are there to keep dust and other contaminants out, how would grease get through the seals to the bearings inside?

There are sealed bearings(rubber) and shielded bearings(metal).

If there is sufficient internal pressure, even the 'sealed' ones will leak, but they do provide greater protection from infiltration.

I prefer the sealed ones, although the shielded ones are quite adequate and are typically what is found in an original motor.

[pennview]

Actually, it was a rhetorical question.