Lubricating an electric motor

[Southern]

It's time to put the rotor back into the stator and reassemble my grinder. Here's an update what the pieces look like apart.

<a href="http://imgur.com/lIqar"><img src="http://i.imgur.com/lIqarl.jpg" title="Hosted by imgur.com" alt="" /></a><a href="http://imgur.com/Al7Xj"><img src="http://i.imgur.com/Al7Xjl.jpg" title="Hosted by imgur.com" alt="" /></a>

My question is, should I grease this rotor before I put it back together? just a skimcoat along the outside, and if so, what kind of lube? Slick50, silicone, white lithium, motor oil, dielectric grease, something else?

Or just leave it dry? No idea.

Thanx!

 

[930dreamer]

The bearings are the only part that require grease.

 

[Alchymist]

The rotor does not touch the stator. Only contact is through the sealed bearings. Older motors with brass bushings or open bearings many have oil cups, otherwise no lubrication needed.

 

[cheechi]

lubrication for a motor? well clearly you need motor oil, silly!

 

[Southern]

Cool, thanks for the heads up, fellas.

 

[Wakefield]

SAE 20 nondetergent service SB ? (For oil cup)
A projector (motion picture machine) shop used to believe in Mobil 1 but that was an old formula when it had just came out.

 

[aussiek2000]

Do not put anything on the rotor. Maybe put a couple drops of thin weight motor oil on the bearings.

 

[vga]

+ 1 on the OP's. Any oil or grease would only attract dust , dirt and act as a heat insulator all of which elect motors hate.

 

[PsRumors]

Zoom Spout Oil found at Ace Hardware is what I use on all of my electric motors that have oil cups.

 

[rlitman]

Do not put anything on the rotor. Maybe put a couple drops of thin weight motor oil on the bearings.

+ 1 on the OP's. Any oil or grease would only attract dust , dirt and act as a heat insulator all of which elect motors hate.

A thick coating of oil = bad.
A VERY think film of something like WD-40 to prevent rust = good. But you do not lubricate the rotor.

The sealed bearings get grease. For motors with an oil cup, I prefer gear oil.

 

[Alchymist]

A thick coating of oil = bad.
A VERY think film of something like WD-40 to prevent rust = good. But you do not lubricate the rotor.

The sealed bearings get grease. For motors with an oil cup, I prefer gear oil.

There are thousands of this type motor out there running with no coating on the armature. Any film will attract dust. Not good. Only time I ever saw rust on a stator was on a motor that had sat underwater for a month, then left without maintenance.....in fact if a motor gets submerged, if it is disassembled immediately, dried off, then baked, lubed and reassembled, 99% of the time it will suffer no harm. By the way, WD40 is not a good long term rust prevention.

 

[Outlawmws]

A thick coating of oil = bad.
A VERY think film of something like WD-40 to prevent rust = good. But you do not lubricate the rotor.

The sealed bearings get grease. For motors with an oil cup, I prefer gear oil.

WD-40 is useless for preventing rust. I just gave it a try on an old Table saw top that we had de-rusted and I left a layer of WD on it as it had to sit outside for a few days. It wasn't particularly damp in the mornings and within 2 days, it had started rusting again.

 

[buening]

Not to hijack, but what is the common use for the 3-in-one electric motor oil as shown below? Is this used for the motors with an oil cup?

 

[Outlawmws]

Not to hijack, but what is the common use for the 3-in-one electric motor oil as shown below? Is this used for the motors with an oil cup?

Yes.

 

[Steinmetz]

WD-40 is useless for preventing rust. I just gave it a try on an old Table saw top that we had de-rusted and I left a layer of WD on it as it had to sit outside for a few days. It wasn't particularly damp in the mornings and within 2 days, it had started rusting again.

It's even more useless as a "lubricant". WD-40 was a Convair development that was used to displace the moisture from Atlas missile skins (stainless), and that's all. But it's been promoted as a universal formulation ever since it was released as a commercial product.

 

[Steinmetz]

It's time to put the rotor back into the stator and reassemble my grinder. Here's an update what the pieces look like apart.

<a href="http://imgur.com/lIqar"><img src="http://i.imgur.com/lIqarl.jpg" title="Hosted by imgur.com" alt="" /></a><a href="http://imgur.com/Al7Xj"><img src="http://i.imgur.com/Al7Xjl.jpg" title="Hosted by imgur.com" alt="" /></a>

My question is, should I grease this rotor before I put it back together? just a skimcoat along the outside, and if so, what kind of lube? Slick50, silicone, white lithium, motor oil, dielectric grease, something else?

Or just leave it dry? No idea.

Thanx!

Why don't you just replace the bearings with a sealed type and call it good? Those bearings couldn't cost more than 15 dollars each. Look for a manufacturer and a number on the side of the bearing, then call a supply house.

 

[PsRumors]

Same can be said about its penetrating abilities Stein.....WD40 doesn't have a place in my shop.

 

[PsRumors]

Not to hijack, but what is the common use for the 3-in-one electric motor oil as shown below? Is this used for the motors with an oil cup?

Yes, I use to use it in my 100 year old fans but then found ZoomSpout oil at Ace. The fans seem to run just a little quieter.

 

[Steinmetz]

Same can be said about its penetrating abilities Stein.....WD40 doesn't have a place in my shop.

It's useful occasionally to start campfires.

 

[Davefr]

Zoom Spout Oil found at Ace Hardware is what I use on all of my electric motors that have oil cups.

Nice sidewinder!!

 

[Alchymist]

Same can be said about its penetrating abilities Stein.....WD40 doesn't have a place in my shop.

I find it useful - great for removing adhesive from labels, and good for machining on aluminum - drilling, milling, etc. As a rust inhibitor - meh - lots of stuff works better.

 

[PsRumors]

Nice sidewinder!!

Thanks!

 

[nanofrog]

WD40 is good for displacing water, such as drying out a wet distributor cap (WD = Water Displacement, 40 = 40th formula).

 

[Southern]

When I reassembled the grinder, I just cleaned the stator and armature real well with electrical contact cleaner and blew it dry with my compressor. After carefully wiping everything off the surface of the armature and stator with a lint free cloth, I reassembled the grinder sans lube.

I did grease up the outsides of the sealed HOOVER bearings with some lithium grease, and soaked the spindle bushings in something similar to 3 in 1 oil. She's all put back together and turns like a DREAM.

I will wire it up tomorrow and post a restoration thread so you guys can see the product of all the advice I've solicited since I got it.

Also, to chime on on the WD conversation, I never really recognized it at being awesome at preventing rust long term, but ******** do I like to hit the parts I clean or polish with it right away to stave off surface rust. I also really love to use it as it's designed, as a displacer and detergent prior to applying a proper lubricant; be it lithium, slick-50, silicone or whatever depending on the project. For getting a surface ready to accept some lube you just can't beat WD in my book.

 

[camarotoolman]

Try some GIBBS oil, its the best.