Motor lubrication

maynah · Jul 25, 2017

I am cleaning up my Sheldon horizontal mill and am not sure what to lube the motor bearings with. Both end bells are plugged with plug screws, so I'm not sure if they need grease or oil. Looking down in them one is clean as a whistle with no signs of grease. The other side has a small amount of grease visible but not much. Access to the motor is tight, so I want to lube it good before I reinstall the motor. I'd also like to install either zerks or oil cups depending. I think it's around 1950 vintage.
Any thoughts?
It's a Marathon 1hp 3 phase motor
Thanks

jdavi581 · Jul 25, 2017

Hello,
I work for Marathon Electric, where your motor was built. I am not sure what they did in the 50s, but everything we do now is much larger and ball bearings. Ball bearings use 2 ports, one to let the grease out and one to let it in. We typically measure the amount going in per SKF's specs plus the space around the bearing in the bracket. Generally, we go for 1/3 full of Mobile Polyrex EM. Being that your motor has a variable sheave, it may be from a furnace blower. Most of these vintage motors use a sleeve bearing, and may be oil. More overall pics my help ID the lube type. I am leaning towards oil since it is so clean inside.
Joe

maynah · Jul 26, 2017

Thanks for the reply Joe. You sound like just the guy I needed to see this.
The mill uses a variable speed drive with a wide, (maybe 1"), toothed belt.
A few more pictures, thanks.

jdavi581 · Jul 26, 2017

Hello,
Reviewing, I would say this is a ball bearing motor. I would make sure the bearings are tight, and if in a tough spot, replace them. I would pump a little grease in there, like two pumps on the grease gun. Is there a pipe plug on the bottom? You do not want to overfill with grease, as you will just pump it into the windings. Can you confirm that it is ball bearing y looking in the hole, and by feel?
Interesting.
Joe

maynah · Jul 27, 2017

I think it is ball bearing. There is a screw under the housing. I'll be sure to have that out when I grease it.
Thanks again Joe.

tdmidget · Jul 27, 2017

I was taught to grease an electric motor by removing both plug and put a grease fitting in one. With the motor running pump grease in until clean grease comes out the other hole. Replace the plugs. This will prevent over greasing.

Gorgoth209 · Jul 27, 2017

Id pull the back of the motor and verify to be sure. But hell since you have it off anyways just replace the bearings. Bearings are pretty cheap these days.

Id guess oil if no drain plug on the bottom. Give the motor a free wheel spin and listen for any noise. If its smooth go ahead and lube but if not id just replace them

Good Luck.

44dwarf · Jul 28, 2017

99% of sleeve bearing motors will have end float that is to say they will float in the axial direction. Larger ones will have scribed line on the shaft to indicat its magnetic center.

padraig · Jan 12, 2022

I have read much on the forum but first time posting here:
A parallel issue: lubrication for a WORTHINGTON 15 hp 3 phase motor. The graphic on the motor plate is from the 30's or later, but "manufactured by Wagner Electric" could put it as late as the 60's. That's all I know.

As to my question for wise and experienced contributors: what type of oil and how much?, how full do I fill the chamber? Any suggestions on flushing out the chambers etc.??

There is a fill and a drain plug on each end. The fill sits at about 4 o'clock position on the arbor, drain obviously underneath at 6 o'clock.
One side has oil - about 3/8" left in the bottom - not sure its doing anything. The other side is dry.
There is a little axial play in the arbor so ?? its a sleeve or bronze bushing bearing? It spins nicely, no obvious grinding. It runs (after mechanical start) on 240 sgl phase with no undue noise or vibration. Thanks for any thoughts

wood2steel · Jan 12, 2022

Joe is dead on! We have used Polyrex EM to service all machine bearings for a while. Great lube and economical! Just don't over grease---

ramsay1 · Jan 12, 2022

Remove purge plug at bottom of bearing housing.. Grease top plug after installing grease fitting... Pump grease into the bearing until you see the grease that is in your gun exit the purge hole... Remove grease coupler from top fitting... Run motor for one minute to purge excess grease..Stop motor... Wipe off excess grease from purge hole and replace purge plug... DO NOT ADD MORE GREASE!.. Many motors have been ruined by grease getting into windings and causing temperature rise....

padraig · Jan 14, 2022

Thank you both. I am confused now. There is oil in the bottom of the lubrication chamber. Do you think I should switch to grease?

reggie_obe · Jan 14, 2022

padraig said:
Thank you both. I am confused now. There is oil in the bottom of the lubrication chamber. Do you think I should switch to grease?

For it's age, couldn't that be a ring oiled motor?
Is that metal strap with 2 screws at the top of the bearing housing? If that's removed does it give a visual of the bearing?

4GSR · Jan 14, 2022

That's definitely a sleeve bearing motor. Use oil only!!! Probably doesn't have a oil slinger, just a pad of felt rubbing against the motor shaft sucking oil from the reservoir below the shaft if the motor is installed correctly.
There's no room for ball bearings in that motor with the shape of the bell housings.

texasgeartrain · Jan 14, 2022

padraig said:
Thank you both. I am confused now. There is oil in the bottom of the lubrication chamber. Do you think I should switch to grease?

Ramsey's instructions are excellent and correct for more modern ball or roller type bearings.

In this case 4GSR is correct. That's an old style motor that takes oil. Could probably have felts inside too. I would surmise you fill oil level to the hole of upper plug. Bottom plug is to do oil changes.

Rob F. · Jan 14, 2022

padraig said:
Thank you both. I am confused now. There is oil in the bottom of the lubrication chamber. Do you think I should switch to grease?

Oil only, those guys are responding to posts from 2017 question, not yours.

ramsay1 · Jan 15, 2022

padraig said:
Thank you both. I am confused now. There is oil in the bottom of the lubrication chamber. Do you think I should switch to grease?

If there is oil in the bottom of the chamber, the motor is likely ring oiled...I have a Westinghouse three phase motor in my small K&T horizontal that takes oil... I use oil from a zoom spout oiler which is turbine oil but a good light machine oil would be correct for a motor with oil wells... Something around 32 I would think.. Cheers; Ramsay 1

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