How to fix an atlas motor?

[Baronjutter]

I've had a very strange problem every since I moved.  All my atlas locos, which were previously great runners and could creep along at very slow speeds for yard work have become my worst runners, if they run at all.

There's no problem getting power, the moment I start to throttle up the loco will begin to hum, louder and louder until it finally starts to move.  On some loco's this is at about half speed, at some it's full speed, on others it never moves at all, just sits there humming with rage.

I took most of them apart for cleaning to see what is wrong.  On all of them the trucks are fine, a bit much of the useless factory grease, which I cleaned and replaced with proper lube where needed.  But all the trucks and gears move very freely, no problem there.

The problem seems to be the motors.  Even when I removed the motors and directly applied DC current it was the exact same story.  A loud hum until the motor is turned up high and then it finally starts moving.  If I help the motor along with my finger it will start at a slower speed, but will rhythmically get stuck or slow down every revolution as if it's getting stuck on something.

Out of desperation I soaked one of my motors in 70% alcohol for a good 10 min then came back and spun and spun the motor with my finger.  The motor seemed a tiny bit better at first, but a few hours later when I checked it again it was back to its old symptoms.  Then I did something stupid, I watched a motor cleaning video on youtube where some kid dunks the motor in alcohol and lets it run for a while.  This did not work for me, the motor would not run, and now it won't run after drying out.  Maybe he was using a more pure alcohol or maybe I didn't pay enough attention to the video, but that one motor is most likely ruined.

I have 7 locos with symptoms like this, I'd love a solution to fix them beyond just buying 7 new motors from atlas because they aren't exactly cheap.  4 of the locos are pretty much new, 3 are used but have date stamps on them showing 2008 or newer, so nothing is ancient stock.

PS
When I moved and packed up all the trains my katos were packed in the same boxes and they all run flawlessly today.  The boxes were never in the cold, and I've left locos not running for far longer than a couple months without problem before.  For some of the least bad locos, if I let the loco run for a while the problem almost gets better but the next day it will be bad again.  It feels like someone poured honey inside my motors or something.

[JSL]

My thoughts would be dry motor bushings. I have had the same symptoms and a lite oiling usually solves the problem.

[Baronjutter]

What oil would you use and where/how would you apply it?

[victor miranda]

I gotta agree the motor shafts and bearings are likely the cause...
I find I am thinking congealed oil.  A motor bearing oil should fix it.
 ummmm .... you will have to run them a bit.
did you oil the motor before  to stored them for the move?

I am trying to decide about the alcohol...
there is not much in the motor that wold be harmed by ethel and isopropl.

Acetone may be the way to clean the bearings.... but I'd strongly recommend removal
of those bearings before the soaking.

from memory the motor should be turning at about 60mw ... 2 ish volts and 25-30 ma
and whirring at double those two.

the hum seems a little odd...  tried a different power pack?

victor

[victor miranda]

What oil would you use and where/how would you apply it?

atlas sells a motor bearing oil.
drip a drop that goes between the motor shaft and the bronze bearing.

if the bearings are dry it may soak up two drops.

wait about 10 minutes between drops the bearings take a little while to absorb the oil.

victor

[Baronjutter]

This is what atlas recommended to me as well, a tiny bit of lube between the flywheel and the motor.  The atlas guy also said I could get some sort of contact cleaner/lube to put inside the motor its self that also improves the electrical contacts with the brushes.

[mmagliaro]

What are you using to test and power these motors?
This part:
"directly applied DC current it was the exact same story"

How are you doing this exactly?
Is it the same power pack you had before you packed all the motors away?

Since the problem seems to be occurring across a large number of motors, I would be inclined to suspect the power source.
While it's possible that some environmental thing affected all the motors, it seems very unlikely.

Try a different power pack.  And by the way, it was a good idea to pull the motors out and test them
on the workbench.  That's the only way to find out what's going on - far away from any geartrain,
DCC decoder, or anything else that could skew the results.

[peteski]

It does sound like a hardened lubricamt causes the motor shaft to stick. I think that at some point Atlas used a lubrincant which would thicken after few years of storage into a honey-like viscosity.

My solution is to clean and re-lube the motor.  I dunk it in an ultrasonic cleaner filled with naphtha, blow it out with compressed air, then put it in a dehydrator to completely dry it out. The cleaning process removes all the hardened lubricant and also cleans the commutator. Then re-lube the bearings with Woodland Scenics light oil (or similar lubricant).  The cleaning removes all the hardened lubricant and also cleans the commutator.

But the same lubricant was also probably used on other mechanical parts of the model. It would make sense to also perform the same cleaning and lube on all the other parts (worms, trucks).  After that the loco should run better than new!

[victor miranda]

about the contact cleaner.

this may have changed....
do NOT let that stuff get into the brush barrels.
it will evaporate and become sticky.  and then your motor will act truly odd
mostly by not running, but sometimes it will use the spring as  the sole means
of conduction.... then the spring becomes a heating element.

be careful with contucta-lube.

[peteski]

I agree with Victor about using only a solvent (which will evaporate with no residue) to clean the motor, then applying lubricant only to the bearings. The commutator and brushes need to remain clean and dry for best performance.

[Baronjutter]

My wife has a little ultra-sonic cleaning thing she uses for her sweaters.  What exact product should I sit the motor in for safe cleaning?

And about the power sources:  DCC system when testing on the track and my tram's DC system when testing the motor directly. All my katos run great and my trams run great too (although could be improved!!)

[victor miranda]

I clean with a toothpick and a paper towel...
I also do not know many who are willing to replace brushes let alone pull a motor apart.

I save the solvents for dire cases.

I am assuming you do not want to pull flywheels.

start simple... have you a thin oil like marvel mystery oil?  air tool oil... NOT wd 40.
set a drop on the motor bearings. keep it away from the shell
I do not think it will cause harm but the red color makes me nervous
it will affect the paint.

you are trying to find the cause of your motor's ailment.
it can be brushes and a clogged com, it is just less likely.
so lets test things.

pick a victim and oil with a thin airtool oil.
that drop should loosen the sticky bearings.

after that does not work.... we do pictures and flywheel pulling etc...

victor

[peteski]

As I already mentioned in my previous post, I use naphtha in my ultrasonic cleaner. It is flammable so caution must be observed (do it at your won risk).  It is an excellent solvent for oils and it does not attack other parts of the motor. It also doesn't leave any residue.   What is good about just dunking the entire motor in the ultrasonic cleaner is that the cavitation of the fluid cleans everywhere (even inside of the brush holders). So the motor is fully cleaned.  Then a drop of oil in each bearing is all that is needed to lubricate it.

Just recently I cleaned an old Minitirx motor (in a 4-4-2 loco - I documented the process in the weekend update thread). You should have seen all the black brush dust that came out during the cleaning.

Naphtha is a paint thinner/solvent sold in hardware stores, usually as VM&P (Varnish Maker's & Painter's) Naphtha. It is also the lighter fluid used in the old fashioned Zippo cigarette lighters.

[victor miranda]

Hi peteski,
I am sure he wouldn't dare to ignore you, unlike me 

I had decided he was off to the hardware store for mmo and naptha.

in the mean time I have to note that an ultrasonic cleaner for a sweater must be pretty big....

give him some time.

[peteski]

LOL!  That sweaters part went right over my head!  He will need several gallons of naphtha for that baby!   

No, no, what is needed is an ultrasonic cleaner in a size used for jewelry cleaning.  I suppose thought that if one had a pirate's chest full of jewels, a sweater-sized ultrasonic cleaner might be just the ticket!