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Offline db60  
#1 Posted : 15 January 2018 00:44:30(UTC)
db60

Canada   
Joined: 27/12/2009(UTC)
Posts: 13
Location: Vancouver,
HI ALL,

Just completed a digital conversion of an old analog 3074 BR216, using LFCM parts from the sticky list, and a decoder from 60760.
When I run the loco, the motor makes a loud buzzing sound at speeds below about 30% throttle. Sounds like gears not meshing. At higher speeds, it runs smooth and quiet.
When I had the motor apart, I cleaned the gears and rolled the bogie across the bench, the gearing seemed very smooth. However with the motor assembled, it makes a loud buzzing sound at low speeds.
I used the correct 8 tooth armature, matching the old 8 tooth one. I've had the motor apart several times looking for a flaw, can't find any. It runs well, No binding or hunting, even crawls at low speed well. Just very noisy.
I am wondering if the gearbox is worn out, even though it seemed fine when initially looked at. But if it were worn out, I would expect it to buzz and vibrate at all speeds?
FWIW, I used the chokes.
Puzzled I am....

Cheers,

Don
Offline db60  
#2 Posted : 15 January 2018 04:17:51(UTC)
db60

Canada   
Joined: 27/12/2009(UTC)
Posts: 13
Location: Vancouver,
The field/magnet was hard to get into the motor housing, but the brush plate lined up with the pins and screw holes nicely.
I'll check this again, based upon the previous post.

Don
Offline jvuye  
#3 Posted : 15 January 2018 16:15:23(UTC)
jvuye

Belgium   
Joined: 01/03/2008(UTC)
Posts: 2,881
Location: South Western France
Originally Posted by: db60 Go to Quoted Post
The field/magnet was hard to get into the motor housing, but the brush plate lined up with the pins and screw holes nicely.
I'll check this again, based upon the previous post.

Don


Same problem as discussed in the following thread (even though not the same loco) ...same answers:recommendations...Wink

3021 Conversion

Cheers

Jacques
Jacques Vuye aka Dr.Eisenbahn
Once a vandal, learned to be better and had great success!
Offline db60  
#4 Posted : 16 January 2018 03:07:53(UTC)
db60

Canada   
Joined: 27/12/2009(UTC)
Posts: 13
Location: Vancouver,
Thanks Jacques, I played with the motor a bit and got it to quiet down. obviously as you say the armature was rubbing.
I ran the loco for about an hour, and then it started to intermittently buzz again 🤔
When removed, the feild/magnet flexes slightly if I pull the open ends apart or push them together. Is this normal? Iam wondering if this is part of the reason. But i guess once the screws are tightned, it should be clamped in one position.
I guess Ill keep playing with the motor,

Thanks for the tips!

Don
Offline jvuye  
#5 Posted : 16 January 2018 11:44:52(UTC)
jvuye

Belgium   
Joined: 01/03/2008(UTC)
Posts: 2,881
Location: South Western France
Originally Posted by: db60 Go to Quoted Post
Thanks Jacques, I played with the motor a bit and got it to quiet down. obviously as you say the armature was rubbing.
I ran the loco for about an hour, and then it started to intermittently buzz again 🤔
When removed, the feild/magnet flexes slightly if I pull the open ends apart or push them together. Is this normal? Iam wondering if this is part of the reason. But i guess once the screws are tightned, it should be clamped in one position.
I guess Ill keep playing with the motor,

Thanks for the tips!

Don


Once it works well, you need to tigthen the screws really well, but of course without breaking them! Wink
Jacques
Jacques Vuye aka Dr.Eisenbahn
Once a vandal, learned to be better and had great success!
Offline db60  
#6 Posted : 17 January 2018 02:50:13(UTC)
db60

Canada   
Joined: 27/12/2009(UTC)
Posts: 13
Location: Vancouver,
well i repeatedly attempted to cure the noise for good, no luck. It still buzzes at below 6 bars on the throttle. Above that, smooth as silk.
So I dissassembled te motor yet again and took my dark blue sharpie and colored he ends of two poles on the armature. The dark blue will contrast the bright green ends, and show if any scratching is taking place. I reassembled the motor and ran it round for a while, noisy, took it apart and the blue was undisturbed. No evidence of rubbing on fhe magnet.
So, unfortunatly it appears to be a gearbox problem. I'll just keep it above 6 bars untill I can source a reasonalbly pricedd gearbox.

cheers

Don
Offline jvuye  
#7 Posted : 17 January 2018 11:20:51(UTC)
jvuye

Belgium   
Joined: 01/03/2008(UTC)
Posts: 2,881
Location: South Western France
Originally Posted by: db60 Go to Quoted Post
well i repeatedly attempted to cure the noise for good, no luck. It still buzzes at below 6 bars on the throttle. Above that, smooth as silk.
So I dissassembled te motor yet again and took my dark blue sharpie and colored he ends of two poles on the armature. The dark blue will contrast the bright green ends, and show if any scratching is taking place. I reassembled the motor and ran it round for a while, noisy, took it apart and the blue was undisturbed. No evidence of rubbing on fhe magnet.
So, unfortunatly it appears to be a gearbox problem. I'll just keep it above 6 bars untill I can source a reasonalbly pricedd gearbox.

cheers

Don


Ok in that case, it's more than likely a problem with the bearings and/or the gears

I start with total cleaning of the transmission using lighter fluid (aka ZIPPO)
I re-lube everything carefully, insisting to completely coat the little gear on the motor shaft .
Be careful on the other side : need to oil, but make sure you don't contaminate the commutator.
Check that every bearing down the transmission receives a drop of oil .

You will notice there is a larger gear at the top of the transmission, coupled with a small pinion.
That one can be a big source of noise too, particularly when there is a bit too much "play" on the axle, induced by a worn out/ out of tolerance axle/bearing .
The gears starts to wobble, and rubs against the body and/or the adjacent gears, until it starts revolving fast enough that the gyroscopic effect stabilizes it.

You should notice geometric patterns (cycloids) created on the adjacent components by the gear's teeth...

I know this explanation sounds a little far fetched, but just try it, there is nothing to loose at this point.

The cure is to coat the sides of the large gear with some grease, or better replace the gear and its axle.
If you have a small press with proper inserts, you can also pop the axle, add a very thin (0.1 mm or less) brass washer which will keep the gear out of arms way...

In extreme cases, I even have drilled out the gear, inserted a custom made (with a lathe) bronze journal before re-assembly.
Never "heard" of that loco again. Wink

Learned these tricks after 60+ years of futzing with Märklin locos...hope this helps

Good luck
Jacques Vuye aka Dr.Eisenbahn
Once a vandal, learned to be better and had great success!
thanks 4 users liked this useful post by jvuye
Offline db60  
#8 Posted : 17 January 2018 23:42:33(UTC)
db60

Canada   
Joined: 27/12/2009(UTC)
Posts: 13
Location: Vancouver,
Originally Posted by: jvuye Go to Quoted Post

The gears starts to wobble, and rubs against the body and/or the adjacent gears, until it starts revolving fast enough that the gyroscopic effect stabilizes it.



I think this is exactly what is occuring. I'll get some lighter fluid, do a thorough cleaning of the gearbox, and lube it as you suggest.
I'll report back with my findings.
I do not have, nor access to, a small press so the above will have to suffice for now.

Best Regards,

Don
Offline jvuye  
#9 Posted : 18 January 2018 13:36:24(UTC)
jvuye

Belgium   
Joined: 01/03/2008(UTC)
Posts: 2,881
Location: South Western France
Originally Posted by: db60 Go to Quoted Post
Originally Posted by: jvuye Go to Quoted Post

The gears starts to wobble, and rubs against the body and/or the adjacent gears, until it starts revolving fast enough that the gyroscopic effect stabilizes it.



I think this is exactly what is occuring. I'll get some lighter fluid, do a thorough cleaning of the gearbox, and lube it as you suggest.
I'll report back with my findings.
I do not have, nor access to, a small press so the above will have to suffice for now.

Best Regards,

Don


Ok, good luck.
If you don't succeed and I were still living in California I would have suggested you send me the power bogie....but I live half way around the earth now..Wink RollEyes

Jacques Vuye aka Dr.Eisenbahn
Once a vandal, learned to be better and had great success!
Offline Donb  
#10 Posted : 21 January 2018 20:42:04(UTC)
Donb

Canada   
Joined: 03/04/2013(UTC)
Posts: 288
Location: Fraser Valley
well I cleaned and lubed it with grease and while it started quiet it quickly became noisy again.
I'll order the new gearbox, luckily it is avail. It uses the Dcm motor parts, but I have those in my spare parts bin.
Thank for the help, Jacques!

Regards,

Don
Best Regards,
Don
___________________________________________________________________________________
CS3, ( Commander is now retired) , C track and Z scale, mostly DB/DR and SBB, SJ
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