Defective Lionel Motor Brushes

Maybe you can use one in a smoke unit

High resistance brushes would decrease the current draw. I think you need to take a hard look at the situation and see if you can figure out what is going on. 

Thanks for the tip. I was going to order some brushes during the Lionel parts sale, but now I'll skip.

The brushes that I have been buying for years have various coloration. Some do have a coppery appearance. Others look more silver, and some are just grey. All work just fine, so I don't think you can go by color alone.
When I am in my shop later, I will have to try measuring the resistance of some. Maybe I'll break out my Wheatstone bridge, that's interesting to play with.

Folks should be aware that as Gregr points out, there are differences in the quality of the brushes that are available. The oldest ones I purchased over 30 years ago, which were probably the first reproductions available, were very hard, and I did not like using them. The reproductions I purchased from George Tebolt, Jeff Kane (Train Tender), and Town & Country are good. I think the best were the ones I got from Madison Hardware in NYC.

The Madison Hardware brushes have a copper tinge, and are fairly soft. They have a chamfer on one end, and are not slotted to hold the hairclip style spring in place. I usually use a file to create the slot. They wear faster than harder brushes. I rather have some extra brush wear, as opposed to wearing the commutator.

It's my impression that those brushes actually have an 8040-?? number, and either came from Lionel, or the same source they used.

David Johnston posted:

High resistance brushes would decrease the current draw. I think you need to take a hard look at the situation and see if you can figure out what is going on. 

David, you are correct. I should have stated voltage increase instead of current increase. These brushes also cause overheating of the brushes and motor field in conventional locos with mechanical e-units. Since each and every engine develops a problem with these brushes, I concluded that the brushes are the source of the problem without the need for an exhaustive engineering analysis. 

I measured an assortment of new brushes using an old analog bench meter that was handy. First I cleaned the probes with Caig Deoxit to get the best readings. The results were surprising. I hope somebody from Lionel will comment on why their brushes were changed to have such relatively high resistance, and what it means.

Here are the results:

2020 original (copper colored) brushes   2/10 ohms
2020 reproduction brushes          4/10 ohms
1661 original (copper colored) brushes   2/10 ohms
1661 reproduction brushes          2/10 ohms
622 original brushes (copper colored)     2/10 ohms
622 reproduction brushes         4/10 ohms
622 Madison brushes (8040-??)          2/10 ohms
8507-150 shunted brush (oldest purchase)  2/10 ohms
8507-150 shunted brush (older purchase) 4/10 ohm
8507-150 shunted brush (2015 parts sale purchase) 2.5 ohms

The  brushes that I call original are truly copper colored, not just a copper tinge. The 2020 reproduction brushes are grey. The 8040-?? brushes are a silvery color with a tinge of copper. The other reproduction brushes are grey with a silver tinge.

I have some motor brush manufacturers bookmarked, I think I am going to see if they say anything about brush resistance.

Interesting stuff.

C W Burfle posted:

I measured an assortment of new brushes using an old analog bench meter that was handy. First I cleaned the probes with Caig Deoxit to get the best readings. The results were surprising. I hope somebody from Lionel will comment on why their brushes were changed to have such relatively high resistance, and what it means.

Here are the results:

2020 original (copper colored) brushes   2/10 ohms
2020 reproduction brushes          4/10 ohms
1661 original (copper colored) brushes   2/10 ohms
1661 reproduction brushes          2/10 ohms
622 original brushes (copper colored)     2/10 ohms
622 reproduction brushes         4/10 ohms
622 Madison brushes (8040-??)          2/10 ohms
8507-150 shunted brush (oldest purchase)  2/10 ohms
8507-150 shunted brush (older purchase) 4/10 ohm
8507-150 shunted brush (2016 purchase) 2.5 ohms

The  brushes that I call original are truly copper colored, not just a copper tinge. The 2020 reproduction brushes are grey. The 8040-?? brushes are a silvery color with a tinge of copper. The other reproduction brushes are grey with a silver tinge.

I have some motor brush manufacturers bookmarked, I think I am going to see if they say anything about brush resistance.

Interesting stuff.

 

Thanks for independently verifying this issue. It looks like most brushes should have a resistance of about 0.2. 

It doesn't require much imagination to see what has happened. Copper is expensive. Chinese manufacturers are cheap. Surprise!

GREGR:  I hope you will  CONTACT LIONEL and ASK them why the problem with the brushes.  The direct contact is important;  as hoping that they read this blog is simply not enough.

               Lionel needs to go to the bin and re-qualify the  brushes or just destroy them,  and have new ones made that are correct.  There is enough  SUB-STANDARD product coming from the Chinese manufacturers on the marketplace today, and this hits at the very heart of our trains !

          I almost sounds like a fiendish  plot ( and right at Halloween) against us  PULMORE MOTOR runners to wipe out our locos so we need to buy new ones!

          Let us know what response you have.  Dennis M.

Just curious: does Lionel make any new product that uses these 8507-150 brushes? If not, how long has it been since they did (and what was the product)?

Also, I edited my post above to correct an error. My most recent purchase of those 8507 brushes was during the last Lionel parts sale, so that would have been in 2015. Apparently these higher resistance brushes have been coming from Lionel for a while.

They still use them to this day in conventional classics, F-3's, and Alcos, and Geeps. That is why they still stock them.

They still use them to this day in conventional classics, F-3's, and Alcos, and Geeps. That is why they still stock them.

I guess I just don't know the recent product line any longer. I purchased a couple of conventional classics when the series started. I thought they discontinued the line. I looked at a couple of recent Lionel online catalogs, and tried searching for pullmor. The only results were for trademark information.

What was the last piece they made?
Update: searching the Lionel web site for "Pullmor" returned 9 diesel locomotives, all cataloged in 2014.

2014 as of now was the last of pulmor motors.  You can bet they will re-surface again.

LOL, I am not a betting man. Mechanical E-units might make a comeback too.

As far as the brushes goes: I wonder whether Lionel has used these high resistance brushes in any of their product. They may not realize that there is an issue.

I guess it's also possible that the newer motors call for a high resistance brush. When I searched the web for information on brush resistance, I found that they are available with different resistance characteristics, but I did not find anything to explain why different resistances are needed.

I found this web page on high resistance brushes. High resistance brushes

I found some other replacement 622 brushes and measured their resistance, which was about 1 ohm.

I was hoping that someone like Mikado or Dennis Waldron would comment on brush resistance. How much is too much?

The other thread going on brushes reminded me that I had to check the shunted  brushes I have on hand to see what resistance they have, and sort out the ones that should not be used.  
It turns out that the last two lots of brushes that I purchased directly from Lionel Service have a resistance of approximately 2.5 ohms. I also have a lot that measures about 0.4 ohms, and some older ones that measure about 0.2 ohms.

Since nobody ever answered the questions, I am going to restate them:

What should the resistance be?
How much resistance is too much?
Does the design of Lionel's last open frame motor require these higher resistance brushes?

In looking at post war commutators, there is typically arcing damage at the edges of the slots.  The is most noticeable on whistle motors which only run in one direction. This might argue for a higher resistance brush. It may also explain why in later years Lionel used brushes with a reduced surface area. Post war motors ran with brushes with very low resistance. They were a mostly copper, which explains the copper tinge to the brush color.  There were also brushes with copper plating. I have always assumed that was an effort to improve electrical contact between the brush tube and the brush.  These would have a copper color.  Some early brush tubes were silver plated, probably for the same reason.  There was a design change in the 700E where Lionel went to brushes with shunts.  The shunts were used in the 700E, the 763E, 701 and the 227 family of locomotives.  Then the use of shunts was discontinued for over 70 years.  It sure would be interesting to learn that story.  

The information I have on the brush composition is as follows.  Note that the accurate measurement of very low resistance is difficult. My guess is that Lionel determined the resistance of the brush by running a current through it , measured the voltage drop, and then calculated the resistance.   This would let them check the resistance at the operating temperature of the brush.  

OO1M-33, 71.8% copper, 28.2% carbon

1-92, 25.15% copper, 74.8% carbon, resistance .000588 ohms

226E-92, 71,8% copper,28.2% carbon, resistance .00019 ohms, .0005" copper plate

622-121 and 2020M-33, Morganite Co. Brush grade CM-3, .0005" copper plate

1001M-46, 1661E-29, and WS-110, 74.8% copper, 25.15% carbon, resistance .000358 ohms

622-202, 2055-12, 50-82 and 0500-101, composition #14

This information is just a snapshot in time.  Things were always changing.

I try to run post war brushes in post was equipment.  I believe that Lionel, during the post war era, had a good engineering department and took design details seriously.  This may have also been true again for a little while when Lionel was in Detroit.  Currently I think Lionel leaves many of the design details up to their contract manufactures.

I do not like to run the newer, mostly carbon, brushes because they are soft and wear quickly.  The resulting carbon dust gets all over inside the motor.  Maybe it is because I am use to working with much higher voltage motors, but I do not like conductive dust all over the insulating material.  The brushes are functionally too soft if the commutator gets blacks streaks on it.   I do not see the high copper brushes resulting in excess commutator wear.  There does seem to be a lot of grooving, which I do not understand the reason for.  But the grooves can be sanded out fairly easily leaving a flat smooth commutator service.  The down side of this is that the commutator bars are fairly thin, maybe 18 gauge, so there are not a lot of refinishes in the commutator.  

The method I use to sand the commutator keeps the commutator surface perpendicular to the armature shaft.  Using this method I have noticed that some commutators have wobble in them.  Not sure how much, but I would guess 5 to 10 thousandths.  This means every time the armature revolves the brushes are forced up into the brush tube.  Then as the armature continues to rotate the brushes come back down.  While the brushes are accelerating down the spring tension will be reduced resulting in arcing.  Sanding the commutator perpendicular to the armature shaft removes the wobble, but can take quite a bit of time.

My preference would be to stay away from high resistance and/or high carbon content brushes in post war equipment.  I do not have enough experience with more modern equipment to express an opinion.

I suspect that the higher resistance brushes may be intended for more modern equipment with electronics.  The large voltage spikes generated by commutation are probably too much for the drivers if you use very low resistance brushes.  Note that the 1uf capacitors across the brushes of any modern Pulmore motor powered locomotive are a lot more effective at damping out noise spikes if there's some resistance before you encounter the capacitor, hence the higher resistance brushes.

Thanks to David and John for responding to my questions.

I was wondering whether my method of measuring the resistance of the brushes was meaningful, so I decided to do a little testing. I cleaned the commutator plate and brush tubes on a spare Modern era small steam engine motor.  I disconnected the wires from the brush tubes, and installed a few different pairs of new brushes.  Then I measured the resistance across the brush tubes, which would include the resistance of the armature, brushes, and brush tubes. A Simpson 260 was used for measuring. As I rotated the wheels, the needle jumped around quite a bit. The numbers reported below are the repeatable low values.

low resistance brushes (.2 ohms)  - total resistance 2.2 ohms
High resistance brushes, measured at holders without pigtails connected - total resistance 18 ohms
High resistance brushes, measured at pigtails, without pigtails connected - total resistance 10 ohms
High resistance brushes, pigtails soldered to brush holders, measured at solder joints - 10 ohms
Original, dirty brushes (8040-150 with slots), measured at holders - 3 ohms

I tried running the motor with the high resistance brushes with the pigtails connected.
I  saw sparking, and as GregR experienced, they got hot very quickly.

Then I reinstalled the low resistance brushes and ran the motor again.
I did not notice any appreciable difference in sparking, the brushes stayed cool.

It would be interesting to know how the design of a motor would have to be changed to allow the use of a high resistance brush without overheating them.

If Lionel did go to the higher resistance brush intentionally, it would have been nice if they had assigned a new part number, instead of creating problems for people with older Lionel trains, which does include pieces that were made not all that long ago.

The 10 ohms is pretty surprising, that will heat those brushes up a lot with any sort of current flowing through them!  If the motor is drawing half an amp, which is certainly possible with a Pulmore motor, that's five watts of power being dissipated in the brushes, they will get toasty hot with that kind of power dissipation  With 18 ohm brushes, it would be even worse!

Another problem with high resistance brushes is the voltage necessary to develop the same power will be significantly higher, with 10 ohms vs. 2 ohms, you'd need four volts more and the same half an amp to develop the same power.

Its disappointing that someone from Lionel has not commented. These brushes were purchased directly from the Lionel parts department. How about it Conrail6358?

Ten months later, and still nothing from Lionel.
Anybody order brushes from the Lionel parts department lately?

I try to use postwar NOS.  I like the copper graphite brushes Lionel used. They are probably not the best thing for the commutators, but many lasted 50 years or longer. At that rate I will never see another brush change. My guess is that Lionel does not control the design to that level.  They probably have no idea what brushes they are getting in these modern locos.  

I don't order those shunted brushes with that problem anymore. They might have replaced their stock (or maybe not since they have done away with Pullmors), but I don't feel like finding out. It's not worth overheating of the motor and PCB components. I just use the old standby No. 622-121 brushes instead. I haven't seen an engine yet that needs the shunted brushes "or else". 

 I try to use postwar NOS.  I like the copper graphite brushes Lionel used. They are probably not the best thing for the commutators, but many lasted 50 years or longer. At that rate I will never see another brush change. My guess is that Lionel does not control the design to that level.  They probably have no idea what brushes they are getting in these modern locos.  

The problem with postwar NOS is finding them.
I have some that I am saving for favorite engines. 

Generally I use reproduction brushes.
I've gone through my supply and made certain their resistance is within reason.

Those high resistance brushes I purchased from Lionel have been put aside in a labeled bag, as have those early reproduction brushes that were too hard.

David Johnston posted:

There does seem to be a lot of grooving, which I do not understand the reason for.

I'm going to venture a guess that it has to do with the composite nature of the brushes.  Copper and graphite have different hardnesses, and, as the brush wears and deposits particles on the commutator, grooves are worn onto the commutator face by harder particles (burned carbon, perhaps?) 

Mitch

This thread originated back in 10/2016.
Never a word from Lionel or any of the people directly associated with the company.