[billericaybill]

I have bought a new Fleischmann 4-4-0 with tender drive and low speed running is very jerky. Medium speed running is fine. The pick up is fine as I can see the wheels moving between jerks forward and the valve gear seems smooth enough when rotating the driving wheels by light finger pressure. I have run it for an hour each way at various speeds without any sign of improvement. Each jerk forward is about 4 sleepers worth. A few questions.. ..Is this a known problem with a known solution? Are all Fleischmann 8 wheel tender drives the same as i would not want to buy another ? Do I just send it back ?..probably about $100 worth of postage 2 ways. Would like to hear any advice or comments.
Thanks, Andrew

 

[Richard Johnson]

QUOTE (billericaybill @ 8 Dec 2008, 22:24) <{POST_SNAPBACK}>I have bought a new Fleischmann 4-4-0 with tender drive and low speed running is very jerky. Medium speed running is fine. The pick up is fine as I can see the wheels moving between jerks forward and the valve gear seems smooth enough when rotating the driving wheels by light finger pressure. I have run it for an hour each way at various speeds without any sign of improvement. Each jerk forward is about 4 sleepers worth. A few questions.. ..Is this a known problem with a known solution? Are all Fleischmann 8 wheel tender drives the same as i would not want to buy another ? Do I just send it back ?..probably about $100 worth of postage 2 ways. Would like to hear any advice or comments.
Thanks, Andrew

*** if its the 3 pole armature then its smoothable to a fair degree.

You will need to remove any suppression components totally first, then set controller and decoder to 128 speed steps and have some reasonable momentum set as step one (try both CV3 and 4 set to 20).

Then..... CV5 Vmax to about 80% of decoder max setting (look at the book - it'll be 64 or 255 depending on the brand), CV6 Vmid to about 70% of whatever U set Vmax to.

After that is time to play with the back EMF a bit.

Richard

 

[billericaybill]

Well thanks for that Richard, my thoughts were to try and sort the mechanical problems before going dcc with it. I am surprised it can be fixed with dcc settings but hey I am happy to learn. Do you reckon a really long run would help, like 12 hours ? Was getting pretty warm after 20 mins leading me to suspect all might not be well in the motor.
Also the fix does not really answer why it is so poor to start with.
Regards, Andrew

 

[Richard Johnson]

QUOTE (billericaybill @ 8 Dec 2008, 23:28) <{POST_SNAPBACK}>Well thanks for that Richard, my thoughts were to try and sort the mechanical problems before going dcc with it. I am surprised it can be fixed with dcc settings but hey I am happy to learn. Do you reckon a really long run would help, like 12 hours ? Was getting pretty warm after 20 mins leading me to suspect all might not be well in the motor.
Also the fix does not really answer why it is so poor to start with.
Regards, Andrew

***All the running-in in the world will not help. The problems are electromechanical (motor design) not simply physical.

The first line in my reply has the key point. The large flat pancake motors 3 pole armature - the hesitation you see is the motor "cogging" between the poles, because as each pole has to cover 120 degrees and the forces rise and decline during its arc, it cannot do that smoothly, as when each pole leaves and enters the magnetic field there are changes & gaps in the forces making it happen so the armature slows then is pulled rapidly to the next position by the magnetic field.

With only 3 poles, it will smooth out at a slightly faster speed but its always going to have a certain roughness when run at slower scale speeds without a lot of help from a well tuned decoder...

The more poles, the smoother the motor is, and if they are skew would in a can motor even better, as one is entering at the same time one leaves, so the forces balance and the rotation is smoother.

Richard

 

[Brian Considine]

QUOTE (Richard Johnson @ 8 Dec 2008, 14:37) <{POST_SNAPBACK}>With only 3 poles, it will smooth out at a slightly faster speed but its always going to have a certain roughness when run at slower scale speeds without a lot of help from a well tuned decoder...

Richard - the 4-4-0's use a can motor with flywheel mounted at right angles to the axels & are usually silky smooth - this particular one would appear to have a tight spot on the gear train. Incidentely, although a 4-axel tender they only drive on 2.

 

[zmil]

Hi Andrew

Brian has a point , there are 3 versions of motor for most of the tender drives

(1)The Old style 3 pole , as Richard pointed out , has been the Fleischmann motor since 1958 (and based on even earlier design) and is not that good at running slow. It can be tweeked with CV adjustment , the BEMF decoders without any CV adjustment will cause it move forward in little surges at slow running speed . ESU decoders have a nice adjustment suggestion in their manual for Fleischmann early Motors and it works very very well.
With most of mine on TCS decoders I have changed the basic speed control CV2 (start volts) to around 20 CV6(mid Volts) = 100 and CV5 = 200

Increasing the Start volts stops that surging at slow speed

(2)The second is the "can" type motor without flywheel these usually are very smooth anyway , but remove the capacitor.

(3)The third is "can" type with Flywheel and once again remove the capacitor

The loco may also need some running in as they are only just tested for a short run at the factory for a few minutes
I found that they do warm up a bit for the first hour of operation (even after changing Motor backplate or adding new brushes) but then after that they are OK

Hope this helps

Regards

Zmil

 

[Brian Considine]

Hi Zmil,

Don't forget that there is also a "1a" - the old 3-pole with "flywheel" built round the armature - I have found that these can run a little too warm, so when converting to DCC I usually replace the armature with the standard type.

 

[zmil]

I will have to look out for that one Brian , I suppose you can only see it when the motor backplate is removed

Most of My loco's have been the older type with the exception of the P8 - BR 038 which had a can motor without flywheel
and that was quite smooth at slow speed without changing anything on the CVs

Regards

Zmil

 

[Brian Considine]

QUOTE (zmil @ 9 Dec 2008, 10:39) <{POST_SNAPBACK}>I will have to look out for that one Brian , I suppose you can only see it when the motor backplate is removed

That's it - to be honest I don't think it adds much, if anything to the performance.

 

[billericaybill]

Progress on jerky running 4-4-0. I took the tender lid off and yes there is a longitudinal can motor with flywheel. There seems to be a greasy substance on the gears and I cleaned some of it out with a fine screwdriver tip. After poking around in such an exploratory fashion I put it back on the track and things are somewhat improved. So I am thinking there might be some grit stuck to the gears by this grease. So I will have to find time to do this in a thorough way tooth by tooth on all gears. Better than having to ship it back to Germany though if this works. Thanks for the tip Brian as it made me examine the gear train which does seem to be the problem.
Andrew

 

[zmil]

Hi Andrew

Glad you are getting to the bottom of it
is the loco the DB, class 13.10-12?

Regards

Zmil

 

[billericaybill]

4-4-0 final instalment. I am very reluctant to mess with new locos unless i have to and then only wanted to do the minimum so i did not void any warranty. I cleaned out all the valleys in the worm gears with a fine screwdriver and did remove various bits of fibre and general detritus which was very small. Its very hard to see the surface of black delrin gear and worm under a desk lamp and be sure of what I am seeing. It then occurred to me that the motor could be easily removed (nice engineering fleischman!) this enabled me to take a brass wire brush to the worm and give it a good going over. I then reassembled it and put it back on to the track...definite improvement. So I gave it a good thrash round for half an hour while I contemplated whether i wanted to strip the whole drive unit down as I am not a talented mechanic. the noticed it had got very hot so left it for the night. Next morning and it runs like a Kato at a crawl and really thats what i pay my money for. So happy now but surprised i had to do that with a good quality loco.

Yes its a Br 13-10.12 Zmil but not sure what that means. Br 13 seems to include various pre DRG 4-4-0's but not sure about the rest other than what I read in the catalogue. Perhaps you could enlighten me ?
Andrew

 

[Richard Johnson]

** Well done Andrew - I should have stood back as I really didn't think laterally enough about this one having the FL 3 pole motor fixed in my mind! I'm very pleased you have it sorted and working well!

Richard

 

[Brian Considine]

Glad to here that all is now well - have to say it's unusual with a Fleischmann !

 

[zmil]

It is unusual from Fleischmann , as they test each loco before packing (not a random one from a batch as other manufacturers do). The Testers stamp is underneath two numbers signifying the tester and the year(2 digit year)

With the BR no. General Class is BR13 then there are sub classes so your version is BR13.10-12

The BR18 for instance has quite a few subclasses depending on which rebuild

Regards

Zmil