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Offline Joach78  
#1 Posted : 08 October 2015 12:30:12(UTC)
Joach78

Belgium   
Joined: 03/12/2014(UTC)
Posts: 7
Location: Namur
Hi everyone,

I have a kind of issue with some of my HO analog locomotives that I can't solve: some of them are running faster in one way than the other (not an huge difference but still noticeable) Confused
Locs are clean and lubricated; pick-up shoes, brushes have been replaced.
I have also noticed that some of them need more "power" to start moving, depending on the direction.
So, I was wondering whether this problem might be caused by a faulty reverse unit, or worn out gears...

Anyone can help?

Thanks in advance!
Offline H0  
#2 Posted : 08 October 2015 13:18:06(UTC)
H0


Joined: 16/02/2004(UTC)
Posts: 15,249
Location: DE-NW
Hi!

Welcome to the forum!

Originally Posted by: Joach78 Go to Quoted Post
So, I was wondering whether this problem might be caused by a faulty reverse unit, or worn out gears...
That sounds like analogue Märklin H0 (you put the question in General MRR without evening mentioning the gauge).

Reverse unit: very unlikely.
Gear: possible.

But most likely the collector plate of the armature is not in the optimal position.
Many locos have a slight difference of speed depending on the direction.

If the speed difference bothers you, maybe try to turn the collector on the axle or replace the armature.
Regards
Tom
---
"In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS
UserPostedImage
Offline Joach78  
#3 Posted : 08 October 2015 13:42:33(UTC)
Joach78

Belgium   
Joined: 03/12/2014(UTC)
Posts: 7
Location: Namur
Originally Posted by: H0 Go to Quoted Post
Hi!

Welcome to the forum!

Originally Posted by: Joach78 Go to Quoted Post
So, I was wondering whether this problem might be caused by a faulty reverse unit, or worn out gears...
That sounds like analogue Märklin H0 (you put the question in General MRR without evening mentioning the gauge).

Reverse unit: very unlikely.
Gear: possible.

But most likely the collector plate of the armature is not in the optimal position.
Many locos have a slight difference of speed depending on the direction.

If the speed difference bothers you, maybe try to turn the collector on the axle or replace the armature.


Sorry, I am new in this forum and have not thought of doing do... I've edited my first post Wink
The collector plate is the black flat part holding the brushes, right?
Offline H0  
#4 Posted : 08 October 2015 14:01:33(UTC)
H0


Joined: 16/02/2004(UTC)
Posts: 15,249
Location: DE-NW
The collector is the copper thingy on the armature (rotor) of the motor. The black thingy is the brush plate. The collector is hidden under the brush plate.
Regards
Tom
---
"In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS
UserPostedImage
Offline Markus Schild  
#5 Posted : 08 October 2015 14:35:20(UTC)
Markus Schild

Germany   
Joined: 14/01/2006(UTC)
Posts: 1,802
Location: Wurttemberg
Hello Joach,

Welcome to the forum.

At traditional Märklin-motors (with a field-coil) it is typical that the speed differs with the direction. The brushes are one reason, the other reason is, that the magnetic strength of the two coils which are together in the field coil differ a little bit. Nothing to worry about.

Regards

Markus

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Offline biedmatt  
#6 Posted : 08 October 2015 14:35:22(UTC)
biedmatt

United States   
Joined: 09/04/2012(UTC)
Posts: 1,343
Location: Southwest Ohio
What Tom is describing is the timing on the motor, or more specifically, when a particular coil will turn on during motor rotation. If the collector is advanced (turned toward or favoring the direction of rotation) the motor will run faster in that direction. If it is retarded, then it will run slower in that direction. So you have a motor where the collector is not at zero timing which will make it run the same speed in either direction. Since it is faster running forward, determine the direction of rotation of the armature when the loko is running forward and then turn the collector slightly in the opposite direction on the armature (anker in German/Marklin speak). You will need to remove the armature from the loko to do this. Be careful, do not move it much.
Matt
Era 3
DB lokos, coaches and freight cars from across Europe
But I do have the obligatory (six) SBB Krocs
ECoS 50200, all FX and MFX decoders replaced with ESU V4s, operated in DCC-RailCom+ with ABC brake control.
With the exception of the passenger wagens with Marklin current conducting couplers, all close couplers have been replaced with Roco 40397.
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Offline Joach78  
#7 Posted : 08 October 2015 14:36:00(UTC)
Joach78

Belgium   
Joined: 03/12/2014(UTC)
Posts: 7
Location: Namur
OK, I see... So I would have to unsolder the wires to reach that part...
Offline biedmatt  
#8 Posted : 08 October 2015 14:38:48(UTC)
biedmatt

United States   
Joined: 09/04/2012(UTC)
Posts: 1,343
Location: Southwest Ohio
Originally Posted by: Joach78 Go to Quoted Post
OK, I see... So I would have to unsolder the wires to reach that part...


No. Remove the brushes from the brushplate and then remove the two screws holding the brushplate to the loko frame. Lift the brushplate away as far as the connected wiring will allow and then remove the armature.
Matt
Era 3
DB lokos, coaches and freight cars from across Europe
But I do have the obligatory (six) SBB Krocs
ECoS 50200, all FX and MFX decoders replaced with ESU V4s, operated in DCC-RailCom+ with ABC brake control.
With the exception of the passenger wagens with Marklin current conducting couplers, all close couplers have been replaced with Roco 40397.
Offline Joach78  
#9 Posted : 08 October 2015 16:06:10(UTC)
Joach78

Belgium   
Joined: 03/12/2014(UTC)
Posts: 7
Location: Namur
Originally Posted by: biedmatt Go to Quoted Post

No. Remove the brushes from the brushplate and then remove the two screws holding the brushplate to the loko frame. Lift the brushplate away as far as the connected wiring will allow and then remove the armature.


Are you sure there is enough play to do so? I tried some time ago but I was not able to move the brushes plate much...
Thanks Smile

Offline RayF  
#10 Posted : 08 October 2015 16:14:10(UTC)
RayF

Gibraltar   
Joined: 14/03/2005(UTC)
Posts: 15,837
Location: Gibraltar, Europe
Originally Posted by: Joach78 Go to Quoted Post
Originally Posted by: biedmatt Go to Quoted Post

No. Remove the brushes from the brushplate and then remove the two screws holding the brushplate to the loko frame. Lift the brushplate away as far as the connected wiring will allow and then remove the armature.


Are you sure there is enough play to do so? I tried some time ago but I was not able to move the brushes plate much...
Thanks Smile



Sometimes the wires are tucked under the interference capacitors or any other handy object with the sole purpose of keeping the wiring tidy. You should be able to free it enough to remove the brush plate without desoldering.

On some locos, however, the screws for the brushplate are not accessible without removing some other part of the loco.
Ray
Mostly Marklin.Selection of different eras and European railways
Small C track layout, control by MS2, 100+ trains but run 4-5 at a time.
thanks 1 user liked this useful post by RayF
Offline Joach78  
#11 Posted : 08 October 2015 17:32:31(UTC)
Joach78

Belgium   
Joined: 03/12/2014(UTC)
Posts: 7
Location: Namur
OK, I'll try again. Anyway, I bought a small loco (3029) second-hand in order to pratice and get used to restoring old Marklin engines... I'll start with this one :-)
Offline Mike863  
#12 Posted : 09 October 2015 04:09:57(UTC)
Mike863

United States   
Joined: 19/06/2013(UTC)
Posts: 61
Location: Florida
Interesting post. I have quite a few older locos that run faster in one direction than the other but have not yet taken any apart to really clean them and fine tune them. For example, the older 3000s including my original all seem to run faster in 'reverse' (cab forward) than with the tank in front. We ran the heck out of it for years mostly in the same direction. Others run better in one direction or the other due to the weight distribution. Be interesting to see what folks have to say.
Offline RayF  
#13 Posted : 09 October 2015 08:31:09(UTC)
RayF

Gibraltar   
Joined: 14/03/2005(UTC)
Posts: 15,837
Location: Gibraltar, Europe
My old 3000s always run faster chimney first. I always assumed they were used to going that way and the wear on the gears made the difference..
Ray
Mostly Marklin.Selection of different eras and European railways
Small C track layout, control by MS2, 100+ trains but run 4-5 at a time.
Offline Joach78  
#14 Posted : 09 October 2015 10:15:00(UTC)
Joach78

Belgium   
Joined: 03/12/2014(UTC)
Posts: 7
Location: Namur
My 3000 runs faster in reverse direction too. By the way, I managed to remove its rotor yesterday, I cleaned it and put it back, but I don't see any difference...(I didn't try to turn the collector as I didn't want to break it).
I think I'll buy a new one, I 'll keep you informed.
Offline Markus Schild  
#15 Posted : 09 October 2015 10:33:49(UTC)
Markus Schild

Germany   
Joined: 14/01/2006(UTC)
Posts: 1,802
Location: Wurttemberg
Hi,

If it's not broke, don't fix it.

As described above it's absolutely normal that classic Märklin-locomotives have different speeds in each direction. I own many. And I don't remind any one which runs absolutely equal in every direction as new locomotives with DC-motors do.

Regards

Markus
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Offline roguico  
#16 Posted : 29 May 2022 21:23:40(UTC)
roguico


Joined: 08/04/2021(UTC)
Posts: 3
Location: Escazu, Costa Rica
Hi,

I have a 3376 rail car that runs twice as fast on one direction than the other. It is an analog unit with an electronic reverse unit and I’m using a while transformer model 6646. The motor is DCM type. The fast direction is what I expect of Märklin locomotives and rail cars but on the slow direction is too slow in my opinion, plus the difference in speed is too much. With the transformer knob to full, on the fast direction the prototipical speed is about 160 km/h, but on the slow direction is about 80 km/h.

I own more tha 50 Märklin locomotives and I’m very familiar with their maintenance. I’ve opened the motor several time, cleaning everything and then oiling where it is needed. The gears turn freely as well as axels, on the first maintenance I put new rubber tires, I even replaced the electro magnet because I measured different values on the two coils.

Today I’ve been doing some test with the body removed and noticed some sparks visible through the brush plate when running in the direction it runs slow, but none whe running in the direction it runs fast. I’m thinking there might be some problem in the armature, probably in the drum collector.

Also, I’ve noticed that it sometimes doesn’t change direction on the first or second try and sometimes after a direction change I need to push the rail car to start moving.

Any suggestions are welcome plus I would like to get schematics of the electronics, does anybody knows where to get them?

Thank you in advance.
Offline kiwiAlan  
#17 Posted : 29 May 2022 21:47:10(UTC)
kiwiAlan

United Kingdom   
Joined: 23/07/2014(UTC)
Posts: 8,067
Location: ENGLAND, Didcot
Originally Posted by: roguico Go to Quoted Post

I’ve opened the motor several time, cleaning everything and then oiling where it is needed. The gears turn freely as well as axels, on the first maintenance I put new rubber tires, I even replaced the electro magnet because I measured different values on the two coils.


I wouldn't be surprised to find the two coils have different resistances, quite possibly 10% difference, because the lengths of the wire on the second (outer) winding will be greater due to the greater diameter as it is wound on top of the first winding.

Originally Posted by: roguico Go to Quoted Post

Today I’ve been doing some test with the body removed and noticed some sparks visible through the brush plate when running in the direction it runs slow, but none whe running in the direction it runs fast. I’m thinking there might be some problem in the armature, probably in the drum collector.

Also, I’ve noticed that it sometimes doesn’t change direction on the first or second try and sometimes after a direction change I need to push the rail car to start moving.


Having to push it to get it moving is typical of a faulty winding on the armature, and this could be the reason for different speed in the reverse direction. However the possibility of a faulty relay on the electronic reverse unit shouldn't be overlooked.

Offline Bryan  
#18 Posted : 30 May 2022 01:27:40(UTC)
Bryan

Australia   
Joined: 08/09/2010(UTC)
Posts: 207
Location: Bowral, NSW, Australia
In all the Marklin locos I have come across, in the analogue locos, there is always a difference between forward and reverse speeds.
On some of the models there can be up to 4 intermediate gears and this in itself can create the difference. The gear train does wear over time and this can give a difference. There are many other factors, the moving of the brush positions for instance with the direction change. The best advise is that if it is running well in both directions, then not to worry.

The comment about excessive arching, this is a major issue. What happens is the edges of the commutator slots wear with arching and take the sharp edge of the off the commutator slots. Excessive running will also do this. Once the commutator is worn like this, the complete rotor has to be replaced. The commutator switching deteriorates and it will run poorly due to bad timing created due to the wear in this area.

With excessive brush arcing, one the most important things to do is to replace the brush springs. Arching creates heat and too much softens the brush springs and the motor goes slower due to less brush pressure. Brush pressure is very important. This maintenance point so overlooked.

David
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Offline roguico  
#19 Posted : 30 May 2022 01:54:06(UTC)
roguico


Joined: 08/04/2021(UTC)
Posts: 3
Location: Escazu, Costa Rica
Thank you kiwialan and Bryan.
Offline river6109  
#20 Posted : 30 May 2022 17:14:49(UTC)
river6109

Australia   
Joined: 22/01/2009(UTC)
Posts: 14,614
Location: On 1965 Märklin Boulevard just around from Roco Square
I would inspect the brushes and the armature (commuter) when too much oil is applied over years the carbon brush will go softer and the graphite will deposit itself between the section of the commuter (3 pole) this will activate arcing as there is no longer a gap between the 3 poles, a good clean of the motor and a change of brushes will help

John
https://www.youtube.com/river6109
https://www.youtube.com/6109river
5 years in Destruction mode
50 years in Repairing mode
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