Adding LED lights to older Bachmann plus dc locomotives Issue

[Len]

I'd say that's a fair assumption. The only small brushes I could lay hands on for my repair shop came from Athearn, Atlas, and Kato. If I couldn't find one of those that would fit, I fell back on various size pencil leads from the local office supply store.

And yeah, cut down Lionel brushes worked in the pancake motors. Although, there are a couple of on-line sites claiming to have pancake motor brushes. I've never used them, so have no idea if they work or not.

Len

[jbrock27]

How did you form the curvature for where the brushes fit against the commutator?

[Len]

I usually used a small "diamond coated" jewlers file. Sometimes I put a small diameter wood dowel in the mini-drill press, slid the lead into a small brass tube to keep it from snapping off, then held the end of the lead against the dowl using gentle pressure.

Len

[jbrock27]

Thank you.

Seems like a job one should be able to get someone in CHINA to do for much less, both in time and cost

[Len]

Your welcome. And the drill press was turned on so the dowel was spinning!

Len

[electrical whiz kid]

Len; I assume the dowel was the same diameter as the commutator...  If they are mis-fit, then bad things might happen to an otherwise very nice motor.

Rich C.

[jbrock27]

...bad things might happen to an otherwise very nice motor.

Rich C.

I would like to point out, the reason for going down that road to begin with was for a lack of availability of replacement brushes, so if one is  in a position of having to replace the brushes, the motor is not going anywhere, anyway, so nothing ventured, nothing gained right?  Plus, what just happened to the "do what makes you happy" philosophy?

[Len]

Len; I assume the dowel was the same diameter as the commutator...  If they are mis-fit, then bad things might happen to an otherwise very nice motor.

Rich C.

It's not super critical, it's only graphite after all. You can leave the end flat and it will wear to the curve of the armature on it's own.

Len

[electrical whiz kid]

Jim;
Yep; you are right.  You do what makes you happy...

Rich C.

[jbrock27]

Rich, it is you who are right and I agree, it's an excellent philosophical approach to life

You can leave the end flat and it will wear to the curve of the armature on it's own.

Len

But in the meantime, doesn't that create a lot of noise when the motor is running, until they take the shape of the curve?  Conducta Lube can only do so much.

[electrical whiz kid]

Jim;
'Twas not my response.  I would have said to find the dia. of the commutator, and this is what you would reference the brushes to when shaping.

In industrial applications, as in with AC synchronous and DC motors, the brushes are usually pre-shaped as per the dia/commutator-and then completed a run-in with no load.  If this is not done, then significant losses of efficiency, as well as excessive heat and damage to the commutator could result.  I would presume that, on a much smaller scale, the same set of mechanics would apply.

Rich C.   

[jbrock27]

Jim;
'Twas not my response. 

Rich C.

I know that Rich.  This question:

But in the meantime, doesn't that create a lot of noise when the motor is running, until they take the shape of the curve?

, was put to Len. 

This all goes back to him having to make brushes to fit a motor that brushes were no longer available for.  Since I already knew that brushes are pre-shaped to the curve of the commutator, I was asking him if they make a racket until the brushes wear to the curvature of the armature on their own.

[electrical whiz kid]

If all else fails, and one cannot find replacement brushes, "rough"-form what you have with whatever means you have that will work; then, once you have them more or less to shape, install them and turn the rotor by hand-slowly-until any drag, roughness, etc. stops.  If the rotor hangs up-stop!  Those commutator segments are delicate!  Then, when you put power to the motor, run it slowly until it is in smooth operation.  This all should be common sense, but it doesn't hurt to review.

RIch C.

[jbrock27]

Thanks Rich. What you say, certainly makes sense, although I find Athearn commutators to be very sturdy and not very fragile.  But here's is one problem with the theory to just run the motor till it smooths out the edge of the commutator; I have an Athearn motor that no matter how much it gets run forward and back, it is making noise at the brushes and commutator running backwards (less in forward).  The brushes are in correctly, everything has been cleaned and polished.  It runs smooth but still makes what I would call a coffee grinding noise when running backward.  No amount of Conducta Lube has helped.  Flywheels have been removed and nothing is hitting the shell.
I have tried getting some help here behind the scenes here, but so far it has been a discouraging noise to get rid of. 

[Len]

Rich, it is you who are right and I agree, it's an excellent philosophical approach to life

You can leave the end flat and it will wear to the curve of the armature on it's own.

Len

But in the meantime, doesn't that create a lot of noise when the motor is running, until they take the shape of the curve?  Conducta Lube can only do so much.

No, it shouldn't make a lot of noise if the ends of the brushes are flat to start with. If there is a lot of noise, I would disconnect the drive shafts and see if it's still noisy when power is applied. If the noise goes away without the drive shafts,  I would be looking at the gears and bearings supporting the gears. Possibly the ends of the drive shafts themselves.

If the motor is real noisy with the drive shafts disconnected, I would look at the armature shaft bearings and make sure they weren't worn. Over time the bearings can wear, allowing the shaft to develop a minute wobble, accellerating the wear as the motor is run even more. Sometimes, if the loco was ever dropped and there are heavy flywheels, the armature shaft itself can be very slightly bent.

The only time I've heard of graphite brushes causing loud noises, was when they were worn down to a thin disk and got tipped in the brush tube.

Len