Motor cogging in one direction only ???

[trainforfun]

This is an Atlas GP38-2 with a decoder .
I removed the motor from the chassis .
I am now testing the motor in pure DC .

In one direction it turns smooth as silk .
In reverse polarity it does not turn fast and it cog like a cog ...

Like one pole is not working in one direction !?!?! 

Brushes ?

[Steveruger45]

Brushes and brush springs would be one of the first things I would check to be sure nothing worn out or broken. When taken out have a good inspection of the commutator too.

[peteski]

I wonder if you mean "cogging"?  What is "clogging"?  I know that clogs are type of footwear.

[OldEastRR]

Peteski, haven't you ever seen a piano in clogs at the beach? 

[peteski]

Peteski, haven't you ever seen a piano in clogs at the beach? 

Of course I have, but I just can't wrap my head around that N scale motor doing what those clogged pianos do at the beach. 

[nkalanaga]

"Clogging" is also a type of dance, but if a motor is doing that, I don't think the repair will be simple.

https://en.wikipedia.org/wiki/Clogging

[ncbqguy]

Part of the confusion is that the term is "cogging" which infers the motor is hesitating in some reqular pattern.
This can be a mechanical issue (which since it is happening in only one direction seems likely) or electro magnetic as was commonly seen on poor three pole motors.
Might be the commutator is warped on one segment  on one side and is hitting the brushes.
Charlie Vlk

[central.vermont]

I'm with Steveruger45 on this one. Most likely its a brush hanging up on the edge of each pole if the comutater as it goes around.
Jon

[trainforfun]

Thanks for all answer , specially the good ones .
The motor is hesitating in one direction , I don't know if it's cogging or clogging , English is not my fluent language .
If you prefer I can write it in french but I suspect most of you will not understand ...
The piano on the beach is not an usual thing to bring but it was to explain how bad the motor was running , have you ever tried to roll a piano on the beach ?

[trainforfun]

Part of the confusion is that the term is "cogging" which infers the motor is hesitating in some reqular pattern.
This can be a mechanical issue (which since it is happening in only one direction seems likely) or electro magnetic as was commonly seen on poor three pole motors.
Might be the commutator is warped on one segment  on one side and is hitting the brushes.
Charlie Vlk

Thanks Charlie !

[Doug G.]

Louis, these guys should have been able to detect English is not your first language.

I agree with the brush/commutator recommendations, especially if the armature rotates smoothly, in both directions, by hand. Or, maybe especially if it doesn't!

Doug

[Bryn]

An issue seen on some British N scale locomotives is when a gear splits between two teeth. This can cause a single direct fault. Normally you can find this be looking at the gears under good light.

[peteski]

Louis, these guys should have been able to detect English is not your first language.

I agree with the brush/commutator recommendations, especially if the armature rotates smoothly, in both directions, by hand. Or, maybe especially if it doesn't!

Doug

English is not my first language either, but properly describing the problem while troubleshooting is vital for a correct diagnosis (I troubleshoot for living, often dealing with Asian customers whose grasp of English language is much, much poorer than Louis').  It can be quite difficult to extract properly problem description from those customers.

I was not making fun of Louis - I suspected that he meant "cogging" all along, but I just wanted to make sure that it was what he meant.  The other thing I want to clarify is that it appears that he removed the motor from that model and is testing t runnign by itself (not coupled to any gearing).  Is that correct Louis?

If the motor is misbehaving while running by itself then that eliminates possibility of any drive-train problems (like cracked gears).

[Doug G.]

He did state he removed the motor from the chassis.

Doug

[trainforfun]

Both brushes are broken in 2 in the middle !!
First time I open this one .
Must have been made early on monday morning or late sunday night if they work 7 days ...

Will replace and see .