Service questions for FM axial air gap motor?

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tobnpr

Hot Rolled

Joined

Sep 27, 2015

• Mar 10, 2020

• #1

Attempting to service an old FM pancake motor on a Tree milling machine.
Can't find a machine manual (MH4/2UV, not UVR) but did find one for the motor. Assuming I can figure out getting the motor off the machine- FM recommended painting the windings with a "good grade of insulating varnish" and flushing/re-greasing the rotor and stator bearings.

Cover off the motor looks to be in amazing shape for probably 50 years old.
Any info on how to clean, prep and "paint" the windings (are there more "modern" products for this?), as well as what type of grease to use to refill the bearings would be appreciated.

 

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TGTool

Titanium

Joined

Sep 22, 2006

Location

Stillwater, Oklahoma

• Mar 10, 2020

• #2

You might try a motor rewind shop for advice or service. I took an older Bridgeport motor to check and they thought the varnish was a little soft so they dipped and baked it for me.

 

9100

Diamond

Joined

Nov 1, 2004

Location

Webster Groves, MO

• Mar 10, 2020

• #3

The right way is to vacuum impregnate it, done in a vacuum chamber where you pump the air out and then let varnish in to cover it. When you let air back in, it forces the varnish into every tiny crack. Some systems put air pressure on it to speed up the process but I never found it necessary.
Then you let he excess drip off and bake at about 260 F. Some shops will tell you that their dipping is just as good, but it isn't. That mostly coats the outsides and large openings in the windings but doesn't get in the small spaces.

Painting the windings with red Glyptal is mostly cosmetic and does little for the insulating qualities.

Bill

 

J

john.k

Diamond

Joined

Dec 21, 2012

Location

Brisbane Qld Australia

• Mar 10, 2020

• #4

If the motor is clean inside ,its probably had a rewind ,maybe not many op hours ago.....Ive scrapped lots of old motors ,and its surprising how many have had costly rewinds just before the machine was surplussed away.Some burnt black too.

 

T

tobnpr

Hot Rolled

Joined

Sep 27, 2015

• Mar 11, 2020

• #5

Thanks.
Anyone have a clue as to what would be a close equivalent/modern substitution for the Fairbanks-Morse FMC08 grease they recommended for the bearings?

 

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GregSY

Diamond

Joined

Jan 1, 2005

Location

Houston

• Mar 11, 2020

• #6

You don't say what shape the windings and insulation are in...do they look OK?

People love to 'clean and bake' windings...that's great if they are oily or greasy or especially dirty. But, if they look OK it's better not to do anything at all.

 

A

AlfaGTA

Diamond

Joined

Dec 13, 2002

Location

Benicia California USA

• Mar 12, 2020

• #7

Wouldn't screw around cleaning and repacking old bearings.
Replace with new sealed bearings...factory lubed and good for the life of the bearing,

Cost is relatively low...
Cheers Ross

 

T

tobnpr

Hot Rolled

Joined

Sep 27, 2015

• Mar 12, 2020

• #8

^^^
Look pretty good to me- but aside from obvious peeling, flaking, etc. I wouldn't have a clue what's "good shape" and what's not...

Another one.
Anyone have a clue if that's a lube location with that screw showing towards the bottom? Manual shows locations top and bottom- nothing on the side (?)

 

Last edited: Mar 12, 2020

9100

Diamond

Joined

Nov 1, 2004

Location

Webster Groves, MO

• Mar 12, 2020

• #9

GregSY said:

You don't say what shape the windings and insulation are in...do they look OK?

People love to 'clean and bake' windings...that's great if they are oily or greasy or especially dirty. But, if they look OK it's better not to do anything at all.

Click to expand...

I did a great many armatures for locomotive fuel boost pumps. The customer would do a megger check and if it showed any conductance, I would bake it at a little higher than 212F, put it in a vacuum chamber overnight, then let in varnish in the morning. That almost always brought the megger reading to infinite resistance. Old varnish can become brittle and crack, making paths for moisture to get in. The baking and vacuum treatment removes all but a minute amount of water.

Bill