Motor Friction and OILING THE COMMUTATOR!!

[TRAINCAT]

I tried the conductive lube made by Atlas. They claim you can lube the brushes and commutator with it. But it too, just like any other oil, quickly fouled the commutators. It also gummed up the pickup rollers. I really see no need to lube the brushes.

Roger

[edw]

servoguy

The oil I used is AutoZone 5W-20 engine oil. 

I am not sure why the oil doesn't cause a problem with continuity through the brushes and commutator, but it doesn't. 

Unlike with transformer oils, where you want to maximize the insulating properties and reduce the electrical conductivity of the oil, typical motor oils, such as the 5W-20 you use, are often formulated with anti-static additives that work by increasing the electrical conductivity of the oil.

[lionelsoni]

I wouldn't be so sure.  A friction torque at the motor is equivalent at the wheels to that actual torque multiplied by the gear ratio.

[EIS2]

servoguy

Brush friction is always a problem with a DC or universal motor.  It is usually the largest component of friction in the system. 

If, by 'system', you are just referring just to the electrical motor, I agree with you.  However, if the system includes the entire locomotive, then I suspect that the brush friction is negligible compared to the total friction in the locomotive.

Earl

[servoguy]

 I was sure I was going to cause a good bit of discussion when I made the first post.  However, I checked the old Hudson (2046) again tonight, and it definitely has very low friction.  It is pulling a tender + 7 cars, most of which are post war with a fair amount of friction.  It will run reliably with the track voltage as low as 9.5 volts.  This is measured near the engine, not by reading the transformer dial. 

 Brush friction is always a problem with a DC or universal motor.  It is usually the largest component of friction in the system.  I speak from long experience using DC brush motors for stabilized gimbals and other precision servos.  It may be that the oil becomes a problem as it ages, but I don't think it will.  The 2046 had been disassembled and the commutator and brushes cleaned before I started this experiment.  I used WD-40 and a soft wire wheel in a Dremel tool to clean both the commutator and the brushes.  The brushes are most likely the original brushes installed by Lionel.  The 2036 was not disassembled and cleaned.  The brush springs in both motors are the ones Lionel installed. 

The oil I used is AutoZone 5W-20 engine oil.  It is what I use to lubricate everything.  So called light machine oils like 3 in 1 are not good as they have a high vapor pressure and get gummy very quickly.  The engine oil has a very low vapor pressure as otherwise it would evaporate from the engine crankcase.  There are better oils to use that have a lower vapor pressure, but they are not readily available.  

I would recommend against using sand paper on the commutator.  The wire brush or other methods suggest in this thread should work better.  

I am not sure why the oil doesn't cause a problem with continuity through the brushes and commutator, but it doesn't.  I am going to continue to use the old Hudson over the next several weeks to see if any problems develop.  I may also oil the commutators on some other engines.

The way to test the effectiveness of the oil is to run the engine by itself and measure the track voltage when the engine is moving very slowly.  This way, the back EMF of the motor is small and the current can be calculated by dividing the track voltage by the DC resistance of the motor.  Conversely, a resistor of .5 to 2 ohms can be put in series with the transformer, and the voltage measured across the resistor and the current calculated.  Do the test on straight track.

Bruce

Bruce

 

[cwburfle]

My primary references were books on electromechanical pinball machine maintenance, and old Radio Hobbiest handbooks. To each their own.

[lionelsoni]

All the Google hits I get about contact cleaning with an eraser seem to be concerned with removing gold or silver plating.  Sandpaper, however fine, would surely remove more plating than an eraser.  But that is not a concern here, since motor commutators are bare, unplated copper.  I am skeptical that an ordinary pencil eraser leaves anything but tiny bits of pink rubber, which are easily wiped or blown off.

[TRAINCAT]

In my own experience with the type of motors mentioned ANY oil on the commutator plate will quickly foul the commutator and cause the motor to slow down, or in cases stop. Only a tiny drop of oil on the armature shaft is needed. Any more than that and it will run down the shaft and get on the commutator and brushes quickly fouling it.

I also find that the new style MPC brushes while softer, will foul the commutator plate by smudging resulting in much quicker fouling. I hate having to disassemble motos to clean them so I found and use only the old copper type post war brushes. They run for many hours between cleanings.

 

Roger

[cwburfle]

Pencil eraser?
Everything I've read about cleaning contacts say not to use pencil erasers because they have chemicals in them that are detrimental to the contact material. I don't see why that would not apply to commutators.
I do the first cleaning with some mineral spirits on a rag. If needed, then I use a fine fiberglass eraser. Finally, I clean any residue with CAIG contact cleaner.
I've experiemented with putting a very light film of CAIG moving contact lubricant on the commutator but found that over time the motor would foul up with dirt faster than a motor without it.
One of the most common problems with Lionel motors is oil fouled brushes.

I am under the impression that brushes a desgined to be self-lubricating
That said, there are all different quality brushes out there.
I have a stock of MPC brushes that came from Madison Hardware (NYC) many years ago.
Last I looked, Town and Country had some of them.
They are very soft and slippery, but the trade-off is that they wear quickly.
Some of the early reproduction brushes I have are quite hard and brittle. I held on to them, but I stopped using them years ago.
If you folks are using poor quality brushes, I suggest you find some better ones. That's alot less expsensive than replacing or rebuilding armatures.

I also wonder whether you guys are using springs with too much tension. Most of the replacement coil brush springs that are available today excert too much pressure, and need to have some loops cut off.
The excessive tension will slow down the motor, and cause quick brush wear (soft brush) or perhaps commutator wear (hard brush).  

 WD-40 is great for tools.
I don't like to use it anywhere on trains.

[Anonymous]

lionelsoni

I wouldn't use sandpaper on a commutator.  A pencil eraser will clean it nicely without any roughening.

I'll second Bob's advice. Sandpaper will scratch, and those scratches decrease the contact area between the brush and commutator. The result will likely be increased arcing, which will decrease the life of the commutator. Never Dull can be used to bring the commutator to a mirror like shine, and it is not abrasive.

[lionelsoni]

I wouldn't use sandpaper on a commutator.  A pencil eraser will clean it nicely without any roughening.

[ripley manor]

 

I have used Marvel Mystery Oil ( available at any auto supply outlet) for the last 14 years on open frame commutators. One drop every third operating session. Never had to replace brushes or had any sticky operation. one of my locos is a 1953 steam outline that had not run in 47 years. M.M.O. on the commutator, 5-40 synthetic on axles and rods, Lucas red n' tacky grease on the gears. operating session are normaly  4hr non stop running 4 periods at the weekend. never tried wd-40 so cannot make any comment on that product.

[jkerklo]

I think there might be something to what  servoguy is suggesting.

My regular servicing of engines includes opening up the motor, sanding the commutator with 320 grit paper, cleaning the slots, then cleaning the plates with alcohol.  Reassemble then oil the armature bearing and felt.   Trains cleaned this way typically run a little slow at first then get back into their normal pace. 

I have had occasion to open the motor of recently serviced trains and noticed oil on the commutator.  After cleaning, the engine would run a little slow, then return to normal.  IT WAS THE OIL RETURNING!  Oil from the bearing was, of course, dripping onto the commutator.  How could it not.

This made no sense, but it seemed to work so I left it alone.  The key might be using the right type of oil, say one made for commutators.

 

John Kerklo

www.Three-Rail.com

 

[Steve W.]

Wd40 is a geat product with many uses however it  is a oil based (fish oil I belive) product. As a rule oil and elect. motors don't mix. Except for the bearings. Also it is extreamly flamable and the fumes in the right conditions(such as trapped in a motor casing ) can be explosive as well. I learned this the hard way. The best way to clean and lubricate an elect motor is to take the time to disasemble it, then clean it with contact cleaner and a soft brush then use a high quality machine oil on the shafts and bearings. There is no wonder spray that will replace taking the time to do it right. You will have a better running motor and no unintentional damage or injury due to fire.......Steve

[Dave Farquhar]

About five years ago the only advice online about fixing Marx engines included sprintzing them down with WD-40. I dutifully did that, and ended up with an engine that didn't run at all--too much oil on the commutator. After cleaning the mess up with some solvent, the engine came back to life.

In desperation, I've applied Rail-Zip or De-Oxit on commutators of motors that wouldn't run, in hopes that oxidation was part of the problem. In all cases, I've ended up having to follow up with a solvent afterwards to remove the oily residue, but sometimes it does seem to help.

I'll buy the idea that a very small amount of oil on the commutator won't hurt, but it's very, very easy to overdo it. If there's too much friction between the brushes and commutator, my first course of action would be to adjust the springs to reduce the tension a bit.

[nickaix]

  I have overhauled a handful of older Lionel steamers with parallel-plate motors and spur gear drives, both pre- and post-war. I have never resorted to oiling the commutator, and I have never had friction problems when I was finished. To me this suggests that the the main friction problem is probably elsewhere, but by reducing the (relatively small) amount of friction between the brushes and the commutator, you have made it less noticeable. Since you spritzed it with WD-40, you may also have unintentionally lubricated the armature shaft, reducing friction there.

Two scenarios do come to mind in which the commutator WOULD be the main source of friction.  One, you have excessive brush spring tension, causing the brushes to put too much pressure on the commutator and slowing the motor. Two, a dirty commutator and dirty brushes are actually sticking together, preventing the motor from starting smoothly, and since you mention that the commutator was dirty, that might actually be your problem.

In any case, oiling the commutator is not usually recommended, since the oil will eventually turn sticky and gunk up commutator and brushes, adding to friction rather than alleviating it.

[overall]

I would think putting it directly on the flat surface of the commutator would interfere with the electric conduction. Have I misunderstood what you did?

George

[sir james I]

Heed Don's warning, WD40 is VERY FLAMMABLE.

[DMUinCT]

WD-40, Water Displacement formula #40, a cleaning agent with "some" lubricating ability.  It is also very "Flammable". 

 I have used it with caution, but, my employer, a very very large company banned its use.  Sad to say, I used WD-40 to free up a "G Gauge" switch, "G Gauge" switch use plastic ties and control box.  I operated the switch and it went up in flames!  Dry it off before using.

Just as Flammable, but recommended by Aristo-Craft (a "G" gauge manufacturer), is CRC 2-26 (Home Depot) as it is a "Precision Lubricant" that is "Plastic Safe" and "Improves Electrical Properties".

 

[servoguy]

 I know this sounds a little unorthodox, but last night I was about to test a 2026 that I had just repaired and lubricated, when I noticed that the commutator was somewhat dirty.  Rather than take the engine apart, I sprayed a little WD-40 onto the commutator.  Then I spun the wheels, and I noticed that the friction was much lower than I had expected.  I ran the engine for a while, and didn't notice anything unusual about its operation except that it would coast a relatively long distance when I shut off the power.  I have a 2046 Hudson steam engine that has had a serious problem with friction. The engine would either run so fast it would leave the track, or it would stall.  I shot a little WD-40 on the commutator, and tested it for friction.  There was still too much friction, so I put 2 drops of 5W-20 engine oil on it and, voila, most of the friction disappeared.  I put the engine on the track, and the motor ran just fine in spite of the oil on the commutator.  So I put the engine on a short train of about 8 cars.  It pulled the cars smoothly around the track with minimal speed variation.  Most of the speed variation was caused by curved track (O-31) as the engine drivers have to slip as it goes around the curves.  It pulled the train at very slow speeds without stalling, and the few times it did stall, I just gave it a slight bit more voltage, and it started again.  In 59 years of playing with Lionel trains, I have never seen an engine do this.  I am going to keep testing this engine to see how often it needs to be oiled, and if there are any problems that show up.  Oiling the commutator is not a problem as it is visible without disassembling the engine.  If I don't find any problems, I am going to oil all the engine commutators.