How Much Brush / Commutator Arcing is Too Much in a Lionel Motor?

[JTrains]

As I'm working to repair and rehab various Lionel motors, I'm trying to get a sense of how much arcing or sparking between the brushes and commutator is normal. Even after replacing brushes and springs, cleaning and (if necessary) dressing the commutator a bit, some motors produce some amount of internal arcing. Others really don't. Sometimes one brush seems more prone than the other in the same motor.  I don't want to obsess over making them perfect - just want to ensure I'm not leaving them in a state where they will wear more quickly than they should have to.

[KRM]

Commutator Arcing is normal. If you have cleaned the brushes and commutator and they run fine and have some arcing I would not worry about it much. 

[servoguy]

In 65 years of having trains, I have never replaced a brush and I rarely clean commutators.  What I have discovered is that poor/no lubrication of the motor will cause excessive arcing and excessive heat.  Use 5W-30 motor oil for everything:  gears, bearings, everything that slides or rotates.  Motor oil never dries out or gets gummy.  

[servoguy]

I do oil the commutators to reduce friction and brush wear.  I have been doing this for 7-8 years with no problems.  Make sure the commutator slots are clean or the oil may release the dirt and foul the commutator.  Not a big deal.

[cwburfle]

Modern electric motor brushes are self-lubricating. Most of the material I've seen on the web recommend against lubricating brushes / commutators.

[Banks]

My Pap (retired electrician from the PRR  Nov '61 after 41 3/12 years of service )  always taught me to keep oil as far as possible from brushes and commutators. This was reinforced by Mr McGregor at Altoona VoTech '71-'73. (He was Pap's "helper boy" when he 1st became a PRR electrician) 

 Smooth polished commutator will arc less. I cringe when people say to use sandpaper. If there is a groove or its out of round I true it in a lathe then polish With fine (400 or 600) grit sandpaper. After it's running a touch with an old fashioned ink eraser will polish it even more. If it still flashes excessively pull the brushes and make sure it's smooth. One or two swipes on the 600 paper will help that.

 

Carbon  (graphite)is a natural lubricant.  Oil usually gums up and causes problems 

[cwburfle]

I use a fiberglass brush eraser for cleaning / burnishing commutators. I purchased a refillable one many years ago in an art supply store. Charlie Clark sold the same ones for years. Unfortunately, that one has been discontinued. The company still makes a similar, metal bodied one. Here is a link:
http://www.eraser.com/fybrglass-brushes-and-erasers/

 

[JTrains]

cwburfle

The company still makes a similar, metal bodied one. Here is a link:
http://www.eraser.com/fybrglass-brushes-and-erasers/

Interesting - which of the various styles / models did you buy?

[JTrains]

Banks

If there is a groove or its out of round I true it in a lathe then polish With fine (400 or 600) grit sandpaper. After it's running a touch with an old fashioned ink eraser will polish it even more. If it still flashes excessively pull the brushes and make sure it's smooth. One or two swipes on the 600 paper will help that.

600 grit? Yikes - I've used 1000 grit 3M Imperial and even that seems a bit too harsh (at least to me).  I've got some 1500, 2000, and 2500 on the way from Amazon so will see how that works.

[sir james I]

I use a 10 cent fingernail file on the brushes. Just a couple strokes to get them shiny. Commutator gets an eraser.

[cwburfle]

Interesting - which of the various styles / models did you buy

 

The model I use is discontinued. It was a plastic refillable model with a fine brush. The closest one made today is E111/F Metal body fine FybRglasss Eraser, part number AA0120. They last a long time. I think I still have an unopened one, and a bunch of refills, purchased as spares from Charlie Clark.