LGB Motor Service

I recently acquired another mallet, and discovered that the front motor was taking 3 amps, which was overloading my transformer.
Checking the threads here, this is because the front motor is full of smoke oil, so I ordered a new motor, but I thought I would have a go at the old one in the meantime.
First I had the brake cleaner to it (note: wear glasses, I managed to get it to splash in my eye) made no difference.
 
So, with nothing to lose, I took it apart. Naturally, I photographed it afterwards, rather than during, so it is all nice and clean.
First there is a plastic collar that pulls off

Then the two brush holders will come out sideways if you use a screwdriver

The brush holders will clean up with the brake cleaner.

I used my fibreglass pencil to clean the end of the brushes.
The commutator will polish with a thin piece of flour grade glass paper wrapped around whilst twizzling the shaft. Then, most important, clean the gunge from between the segments using your scalpel blade.


Reassembly is the reverse of disassembly, as Haynes says. The black brush holder is on the side of the motor stamped buhler.
 
I reckon that the oil mixes with the carbon from the brushes, and forms a conductive paste between the segments.
Anyway, the motor spins with 0.1amp out of the truck, and when re-assembled, the bogie takes 0.2 amps.
 
The engine is zooming round on about 0.6amp with a couple of wagons, so I pronounce it a fix!
I wonder how long it will last??

Attached Image(s)

having done the very same to a water damaged 2017 -it should last-and running seems to only improve so far in my case-did the very same thing, but failed to know that i should scrape the commutator seams
 
i also used a sparing amount of electrical lube on the commutator, and a drop of oil on the shaft ends-and worked the brush plungers as these do hang up sometimes

Excellent step by step guide to repairing LGB motors....

Brilliant thread and exactly what I needed today!
Have 5 stars and a whole lot of thanks. 

Further info, including dealing with later 'can' motors may be found in the thread below.
 
http://www.gscalecentral....237&mpage=1#121334

Cheers Neil,
 
I knew I couldn't be the first to dismantle one, your thread is quite comprehensive.
Seems the key is to clear out the slots in the commutator, as I suspected.
I couldn't see any reason for the high current draw except a commutator short, the motor spun freely enough, and the windings looked perfect, I've seen windings turn black when they cook.
I did add a single drop of oil to each shaft bearing, but didn't add electrolube to the commutator as I thought the brushes should be self lubricatiing.
 
Martin

Does this mean you dont need a motor now?

whatlep


Brilliant thread and exactly what I needed today!
Have 5 stars and a whole lot of thanks. 

Yep, it's often possible to sort out motors with a little TLC as has been explained. It can be very satisfying to restore something to good health that seemed to be on it's death-bed.   I've had success with motors from G scale right down to Z gauge when doing a stint as "Loco Doctor" at my old club's annual exhibition. Trickiest thing I remember tackling was resoldering the coil wires to the commutator on an N gauge motor - not fun but it worked!
 
I'd recommend using something like a wooden cocktail stick or sharpened matchstick rather than a scalpel blade to clean the commutator segment gaps, to avoid risk of slipping and scratching the surface.  A matchstick is also good for cleaning the commutator surface it you cannot get in with a fibreglass pen.
 
Personally I'd avoid using anything like electrolube on the commutator as so often I've found carbon brushes to be degraded where they've absorbed oil. My standard service treatment is to remove the brushes and roll them in some kitchen paper.  I check and adjust the springs for tension.  If a motor has been running hot it can sometimes destroy the tension.  Clean out the brush holders.  Clean and maybe re-profile the end of the brushes before refitting.  Apply bare minimum of oil to the motor bearings then run the motor at medium speed for a minute or so to allow the refitted brushes to bed in, you can see less sparking and hear smoother running as everything settles.
 

My new motor came, but it isn't the right one, or at least it is too big!
 
The engine is a unitah mallet, the instructions say motor 62201.
I measured it as 91mm from one end of the shaft to the other, the one I have received is 120mm from one end of the shaft to the other.
 
Have I ordered the wrong one, or have they sent the wrong one?

62201 is the standard motor. You may have the longer motor (from the Rugens 8 wheeler) which is the similar code 62210

Spot on! The packet has got 62210 on it!
The invoice has 62201 so I got it right.
 
Thanks,
 
Martin

55.5


Does this mean you dont need a motor now?

whatlep


Brilliant thread and exactly what I needed today!

Alas, my motor is the "can" type and beyond my workshop's resources to fix.  So back to square one....

If you follow Neils link in post #5, he shows how to dismantle a can type motor, basically, support the cog and warm it all round with your little cooks blowlamp, whereupon it expands and the motor falls out.
 
With a little careful screwdriver prising and tag bending then the endcap with brushes will come out. Reassembly is awkward, but it doesn't work now, so you have nothing to lose.

a follow up
i found that the electrical lube i use-
leaves a thin anti oxidation film-great for pots and jack inputs
not so great for commutator and brushes, as the fine dust build up intto a greasy thickish film
i re-did my motor removing the rather deep grey film, this time cleaning the commutator ring and thoroughly removing all lube
had to do this when the motors began to slow down-also found the brush springs were rusted trhough-and replaced with a jury rigged tiny spring to do the job

I have the same locomotive, And have had the same problem, leaking smoke oil dripping on the forward engine, 
in my case the motor started to smoke in stead of the smoke generator, by the time I noticed and pressed the emergency stop,
(I had to find the ............. dimax first) the motor wasn't in need of any help anymore 
When ordering buhler motors for LGB there are usally two option the short shank and the long shank, there are only a few lgb models
which have different motors
regarding lubrication and or maintenance fluids be very scars in the use of them when I have motors wich make a little noise I usualy 
apply a few drops of WD40 with a thin piece of messing rod. 
 
rgds Niels

I successfully stripped a failed motor but broke the brushes at some stage. I am told that replacement brushes are not available. Be very,very careful, I now have a useless motor.

van5


I successfully stripped a failed motor but broke the brushes at some stage. I am told that replacement brushes are not available. Be very,very careful, I now have a useless motor.

Champex-Linden list spare brush assemblies (their part number CL30317) for the older type motor.
See towards the bottom of this web page. http://www.champex-linden..._lgb_ersatzteile_2.htm
Chalk Garden Rail http://www.chalkgardenrai...uk/acatalog/index.html are U.K. agents for Champex Linden
If needs be I think it would be possible to remove the brush holders with brushes from these by bending the securing tabs and fix them to the later style motors.
I doubt it would be practical to replace the carbon brushes whilst keeping the original holders. The braid tails on the brushes need to be electrically connected to the holders. If you tried soldering the braid would wick the solder rending the brush tail inflexible.

All the info above has been posted before!!
As in post 5 by Niel:
  
 See this thread: 
http://www.gscalecentral.co.uk/f/tm.aspx?m=1237