LGB motor repair and testing.

Neil Robinson

Neil Robinson

Registered
24 Oct 2009
9,206
520
N W Leicestershire
#2
The above doesn't seem to work now so I've reposted.
Over the years I have had some success decontaminating model railway motors that have become unusable due to excess oil and/or grease.
When I discovered that Mike had some LGB motors in his scrap bin I thought it would be worth trying to resuscitate at least some of these especially as you don?t get much change from £40 for replacements these days.
Two motors duly arrived from oop norf early this year. Testing on no load revealed one was taking way too much current, but the other seemed o.k. on the brief no load test. Both these motors were the latest type that require a degree of brute force to dismantle, it doesn?t help that the worm gear needs to be removed from the shaft at the brushgear end. The obviously duff motor was selected to be the guinea pig and the worm and brushgear duly removed with Mark Biffen?s help. In doing this, and also the subsequent reassembly, I learnt the hard way how to do it properly! A suitable tool was designed and made by Mark to make the job easier in future. This motor now runs o.k. but has sustained a little damage, consequently I wouldn?t wish to put it in a loco. The other motor was put to one side as it appeared O.K.

At Grail three more motors arrived from Mike?s scrap bin . Two were the older type which may be easily dismantled as far as is necessary, the other one was the same more recent type as the two in the previous paragraph. On no load both of the older motors took 1.2A, so they promptly got the treatment. After treatment, on no load, flat out on the same LGB controller as before, they only took 0.1A so they were returned to Mike at Mark?s post Grail party. When I got round to testing the other one, which had apparently been running hot, on no load the current was rather high very briefly but it then settled at an acceptable level. This motor would be the guinea pig for the new improved method of servicing this type using the tool Mark made and the knowledge gained from the first motor.

I decided that it would be desirable to test this motor under load so I gave some thought to a practical method of doing this. Plan A, give the motor back to Mike, get him to swap it for a perfectly good motor in a loco, test extensively and then swap the motors back again. Seemed o.k. to me, but I realised that there may be a short delay in obtaining results!
Plan B, use the motor under test to drive another similar motor as a generator, but what would I use as a load on the generator? Then I had one of my rare light bulb moments, use 12V automotive light bulbs! Right, next decision, what rating of bulb(s) to use. I argued that many simple single motor LGB locos ran fine with LGB?s older 0.5A starter set controllers and the 1A version is often O.K. for twin motor locos with sound and lights, so 0.5A at say 24V i.e. 12W would be a reasonable maximum continuous output for a motor in an LGB loco. If anyone has information on Buhler?s design performance data for these motors I?d be grateful for a copy.
Now all I had to do was design and make the test bed. A trip to my local friendly plumbers? merchant proved that 28mm pipe clips would hold the motor and generator fine so I purchased two. Next, off to my local friendly motor factors. The old boy there wasn?t that busy and was happy to send some time sorting out something slightly out of the ordinary. I came away with a length of clear plastic tube which was a good push fit over the motor worm gear, three 12V 5W bulbs (one spare) and, from some dark recess of the stores, their last two genuine Lucas U.K. made bulb holders. Before mimimans has apoplexy and thinks I?ve taken leave of what little senses I may still have, I argued that these will be used to test the motor and if anything will find a fault and let the magic smoke out they will! I went for two bulbs as I could vary the load by using one on is own or both in series or both in parallel. The whole lot was lashed up on a convenient piece of wood with the first mentioned, slightly damaged, motor as the generator . When connected to a controller via an ammeter it worked!

Flat out , motor input 1.05A 18.5V generator output 0.83A 10.7V. This gives an overall system efficiency of about 45% Simplistically if I allow only 5% losses in the transmission as the tube flexes due to imperfect alignment of motor and generator and 25% loss in each machine then the motor is running at around 75% efficiency which is probably fine for this type if machine. Again, if anyone has more information on this I?d be pleased to hear it.
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KeithT

KeithT

Hillwalking, chickens and - err - garden railways.
24 Oct 2009
12,952
176
Nr Manchester
#3
The link worked for me Neil, minus the .gif files.
 
LVT

LVT

Analogue automated LGB Euro on 4 loops
24 Oct 2009
156
10
Near Atlantic City NJ USA
#4
Neil's reference to the newer version motors prompts me to pass along a recent experience. I purchased a very early 2095 off e-Bay for 100 USD, with the photo description showing that one motor had been removed. I reinstalled one of my resuscitated motors and new power pickups and then checked and lubed the bogey that had remained powered and found that it had a new version motor. After about a year's satisfactory service, suddenly one motor unit stopped working. My immediate reaction was that it was my replacement that had given up, but to my surprise the "new" motor was dead. I had to see; so I opened the case and was shocked to find that the brushes were gone and it had been running with only the metal brush holders hitting the commutator! One of those had now worn away. I have never even replaced a brush on my older style motors; so I guess this is another downside to the new version. Of course I have no idea how many hours/miles were on it.
 
Neil Robinson

Neil Robinson

Registered
24 Oct 2009
9,206
520
N W Leicestershire
#5
KeithT said:
The link worked for me Neil, minus the .gif files.
Ah, probably me then but I'll blame the recent tweeking of the forum.
I can now upload the images which I couldn't do a couple of hours ago so I've left the recent text post and added the images.
 
Neil Robinson

Neil Robinson

Registered
24 Oct 2009
9,206
520
N W Leicestershire
#6
Right, here's an attempt at a 'how to' for motor inspection and cleaning.

I?ve prepared this article using parts of old motors from my ?may come in useful someday box?. There is therefore a possibility that some reversible components may be shown assembled in the incorrect orientation. Rather than find out that your loco goes backwards after reassembly it?s a good idea to mark your motor in such a way as to ensure it goes back the same way as it was.
The principles apply to most model railway motors and the detail applies to standard, long shaft (mogul) and long core (Rugens 0-8-0) LGB Buhler motors.

If you suspect a motor has failed access the loco gearbox, remove the top or, on early ?clamshell?gearboxes carefully remove one side and check for a pair of small, easily lost, steel balls, one at each end of the motor shaft. If present save them as you?ll need to reinstall them if reinstalling the original motor. However if using a later replacement motor LGB?s instruction sheet stated that they must not be reinstalled.
In either case mark the motor top before removal.

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Once out of the gearbox, if possible, test the motor?s current draw running on no load, it should be between 0.1 and 0.2 Amps with around 10V to 20V across the terminals. If it?s a lot more then IMHO it?s worth inspecting and trying to clean it, especially as the motor will probably be scrapped otherwise.
Some 40 years ago one of my previous employers tested various cleaning agents for their industrial motors and generators. Their recommendation, ?Genklene?, ICI?s trade name for 1,1,1-Trichloroethane, is no longer available due to environmental considerations, but Ambersil produce Amberklene FE 10 that claims to be a good substitute. It does the job well in my experience.
http://www.rapidonline.com/Tools-Equipment/Amberklene-FE10-74396 < Link To http://www.rapidonline.co.../Amberklene-FE10-74396

There are two styles of interchangeable motor, one, the earlier style with easily accessed brushgear, and the other a ?can? type motor. I?ll deal with the early one first; it?s easier to photograph the innards.
Firstly note the relative positions of the red and black brush holders and also the locating spigot relative to the motor top.

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Remove the piece with the spigot then lever out both brush holders and remove them.

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Clean both brush holders and the commutator with the solvent and wipe with a lint free cloth or paper. Then clean out the commutator slots with a cocktail stick or pin. Start from the end nearest the windings, left in the picture, and move away from them. If using a pin, or anything harder than the copper commutator, take care not to slip and scratch the commutator segments? surface.

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Check the brushes are in good condition and slide freely in their holders and check the brush springs work properly at the same time.
Reassemble, taking care that the bits go back in the same relative positions as before and then test the motor. A small drop of oil on the outside face of the shaft bearings may be a good idea, especially after a thorough degreasing, but overdo it and it's back to square one.

continued ...........
 
Neil Robinson

Neil Robinson

Registered
24 Oct 2009
9,206
520
N W Leicestershire
#7
For a ?can? motor remove the worm from the connection end of the motor before any other dismantling. I?ve got a slotted piece of steel that supports the worm allowing the shaft to be driven through it. Ensure the motor body is unrestrained otherwise you might partially drive the shaft through the motor, upsetting the relative positions of shaft, armature and commutator. Once the shaft is level with the end of the worm you?ll need some form of drift. I use an old broken twist drill. The end of the worm often suffers a little damage, I?ve pondered heating the worm to ease removal but I?m concerned about heat damage to the plastic motor endplate.

Update September 2011.
Experience has shown that an intense small flame (I use a MAP Gas torch with a small nozzle) played on the worm with the motor supported as shown is effective, the motor drops under its own weight as soon as the worm is hot enough. Unlike the first method the worm suffers no damage.


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Ensure both the motor body and plastic endplate are marked to ensure correct reassembly then cut both suppressor wires half way between points x and y as shown.
Prise out the three steel tabs securing the endplate in position, take care if the screwdriver slips it hurts, don?t ask! Note in this photo the locating spigot part has been loosened, unlike the earlier style of motor this type will only fit one way due to its shape.

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Remove the endplate.

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clean the brushgear, commutator and commutator slots as for the earlier type motor, then check the brushes and their springs. Don?t loose that small plastic washer.

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Unlike for the earlier motor, these brushes need to be retracted into their holders before reassembly, this will release the small plastic washer, put it on the motor shaft and push it up against the commutator. Using a toothpick, or some other similar relatively soft tool push the brushes into their holders far enough so that the springs secure them at the side, but not so far as to protrude beyond the edge where the inner side of the motor?s body locates.

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Replace the endplate assembly in approximately the same position as originally but don?t push fully home. Rotate it slightly until the top of a brush is visible in the nearest cutout to its final position.

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Push the brush down with a toothpick, the spring should then locate on the brush top and press the brush against the commutator. Repeat for the other brush and then push the endplate fully home.

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Bend the steel securing tabs back over, when tapping these into place ensure the motor is supported by the other endplate, and the shaft is well clear of anything underneath. If not, as with worm removal, you might partially drive the shaft through the motor, upsetting the relative positions of shaft, armature and commutator.
IMHO it?s a good idea to test the motor before these tabs are fully home.
If all is well drive the tabs home and rejoin each suppressor wire with a small blob of solder. Too much and it may foul the motor housing, but if you overdo it just file off the excess solder.
Replace the spigot then replace the worm, the hole is tapered so place it whichever way round the shaft goes in furthest.
When finally tapping into place make sure the other end of the shaft is supported with the rest of the motor free to prevent anything other than the worm moving.

Update September 2011.
Alternatively play a small intense flame on the worm until it starts to move under its own weight Use the piece of steel to finally adjust the position.


The shaft should protrude through the worm by the same distance as that on the undisturbed worm on the other end. The slotted piece of steel I use for worm removal is just the right thickness and there is a hole in the opposite end to the slot. This is placed over the shaft and tapped down until the shaft end is level with the top. File away any damage to the ends of the worm. If the damage is too great Champex Linden list spare worms so they may be available from Chalk Garden Rail.
http://www.chalkgardenrail.co.uk/acatalog/index.html < Link To http://www.chalkgardenrai...uk/acatalog/index.html
As mentioned at the end of the previous post a small amount of oil on both bearings may be good, but don't overdo it. Finally reassemble the loco and test.
 
dutchelm

dutchelm

Registered
24 Oct 2009
2,569
123
N Somerset
#8
Unfortunately my can motor was beyond repair after injuries sustained trying to get it apart.
There were 2 earlier motors awaiting disposal so following instructions I dismantled them. One had an open circuit armature & a brush jambed solid which wouldn't move & disintegrated when forced. The other had a sticky brush which was going open circuit.
The final result is that by combining bits I have a working motor.
Thanks.
 
dunnyrail

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
13,499
3,126
70
St.Neots Cambridgeshire UK
#9
Niel, many thanks for this posting. What a super resource.
JonD
 
C

ceejaydee

Big Trains
29 Nov 2009
1,130
0
Far East of Bedfordshire
#10
I have to agree - what an excellent resource.
Takes me back to my teen years stripping and rebuilding Triang TT locos when they were already 25 or more years old.
 
Neil Robinson

Neil Robinson

Registered
24 Oct 2009
9,206
520
N W Leicestershire
#12
Stainzmeister said:
Neil
What was the liquid cleaning method you posted - can't find it !
(Is it possible to dip the whole motor in a form of "de-clagger" to restore it to its former performance ? Call me lazy.......)
One of my Stainz fleet has a poorly motor :mad:
Good evening Lazy! :rofl:
You could dip the motor as you suggest, I'm sure it wouldn't come to harm.
If the motor were mine though I'd dismantle it for three reasons.
I'd like to mechanically clean out the commutator slots.
I'd like to remove the gunge rather than get it into suspension only for it to settle out again inside the can.
I'd like to give the motor a visual inspection that all is well.
Dr. Robinson's highly efficacious motor elixir is available under the trade name Amberklene FE 10.

http://www.rapidonline.com/Tools-Eq...130/?sid=4fe8637d-8b4d-43de-8557-ed22b8a6754e < Link To http://www.rapidonline.co...43de-8557-ed22b8a6754e
 
Madman

Madman

Registered
25 Oct 2009
12,583
1,995
Pennsylvania, USA
#13
I am going to make a copy of your articles for my "Train repair manual". Thank you for an excellent narrative. :clap:
 
V

van5

Talyllyn Railway. I of M, Old Land Rovers
24 Jan 2010
169
4
Great Barr, Birmingham
#15
The only fault I found which may have caused the high current problem on my tram motor was broken brushes. The brush braids appear to be welded to the holder. Any advice on how to replace the brushes would be appreciated. Thank you.
Derek
 
Neil Robinson

Neil Robinson

Registered
24 Oct 2009
9,206
520
N W Leicestershire
#16
van5 said:
The only fault I found which may have caused the high current problem on my tram motor was broken brushes. The brush braids appear to be welded to the holder. Any advice on how to replace the brushes would be appreciated. Thank you.
Derek
The braids are indeed welded to the holder. I fear an attempt to solder new ones in place would most likely fail as the braid will wick the solder rendering it inflexible and therefore useless.
Palmeston's link to Champex Linden in the previous post gives a source of replacement brushes for the earlier motors. The actual brushes and brass brush holders seem to be the same as in the later motors if. It may well be possible to remove your defective brushes complete with holders by bending back their securing tags. If you are successful in this you could do the same and remove replacement brushes and holders from the old style spares and insert them in your motor.
Chalk Garden Rail are U.K. agents for Champex Linden and may have some stock.
 
M

mitchell coe

Registered
25 Sep 2010
71
0
#17
This is great but I simply cannot find anyone who can supply brushes for my motors, even Chalk rail and the linden people do not seem to have them, these are for my yo can motors for my LGB diesel ,23510 and its brushes for universal motor with short shaft 62201, if anyone can help I would be very grateful, kind regards Mitchell
 
spike

spike

It's me
#18
Neil Robinson said:
Stainzmeister said:
Neil
What was the liquid cleaning method you posted - can't find it !
(Is it possible to dip the whole motor in a form of "de-clagger" to restore it to its former performance ? Call me lazy.......)
One of my Stainz fleet has a poorly motor :mad:
Good evening Lazy! :rofl:
You could dip the motor as you suggest, I'm sure it wouldn't come to harm.
If the motor were mine though I'd dismantle it for three reasons.
I'd like to mechanically clean out the commutator slots.
I'd like to remove the gunge rather than get it into suspension only for it to settle out again inside the can.
I'd like to give the motor a visual inspection that all is well.
Dr. Robinson's highly efficacious motor elixir is available under the trade name Amberklene FE 10.

http://www.rapidonline.com/Tools-Eq...130/?sid=4fe8637d-8b4d-43de-8557-ed22b8a6754e < Link To http://www.rapidonline.co...43de-8557-ed22b8a6754e
If you want an alternative to Neil's cleaner
This is what us pro motor people use for cleaning, choose the Meggawash.

http://www.hi-wire.co.uk/acatalog/Lubricants.html
 
D

Dan

Registered
28 Jan 2010
154
14
Eastern MA
#19
To remove and reinsert the worm gear from the LGB motor is is very easy to bend the shaft.

THe way I do it in order not to bend the shaft is to use a small blow torch. Brass expands fast and the worm gear actually falls off the shaft.

Give the shaft time to cool and then heat the gear and reinsert the shaft in the gear, when it cools it is just like it was never off the shaft.

I have done this over 10 times with no motor damage from the heat.
 
owlpool

owlpool

Welsh NG in the mountains. live steam
25 Oct 2009
6,345
329
Brecon Beacons, South Wales
#20
just found this thread and used it to remove and repair the motor from a duff Stainz
the small blowtorch to remove the worm gear worked a treat
the motor is now running, just have to sort out my battery tender now
thanks for posting this very useful advice