Hornby Ringfield - Clicking/Catching Noise

[StrathpefferJunction]

Hi folks.

 

I've got a Hornby ringfield motor that is clicking as it turns. It happens in both directions, but a bit worse in reverse.

 

It's the variation with the bent over tabs that hold the brush springs in place (and tender drive steamer one). Three poles.

 

I've stripped the entire motor down and cleaned it. The brushes themselves are not particularly worn.

 

I've isolated the clicking noise through trial and error down to the brushes. It happens as the brushes passes the gap between the three copper pads on the commutator.

 

Has anyone come across this before? I've googled multiple keyword combinations and I just can't find any threads, but I'm sure others must have comes across this.

 

Any thoughts, ideas or solutions welcome!

 

Thank you very much.

 

David

[stewartingram]

Wrong brushes fitted (Lima perhaps?), which are a loose fit in the hole, so not at 90 degrees to the commutator?

 

Stewart

[StrathpefferJunction]

Unfortunately not. They're the correct ones and a good fit. I've never come across this before, as normally they, by design, slide over the gap between the commutator poles. I'm wondering if could be some delamination between the copper and the (phenolic?) material below, providing for a tiny lip? But, if so, it's very slight.

[johnb]

 I'm wondering if could be some delamination between the copper and the (phenolic?) material below, providing for a tiny lip? But, if so, it's very slight.

 

Could be, or are the edges of the brushes just that bit sharp,possibly slightly misformed/chipped, are they new? Maybe a very gentle rub with a fine emery paper will just take the edge off them.

 

HTH

 

John

[StrathpefferJunction]

I'll definitely check that out tomorrow thanks John. They're not new, but very little wear. It's hard to know with these old ringfields how much to keep trying or just accept it for what it is.

[RAF96]

Fill the gaps twixt commutator segments with epoxy glue then smooth to the same level. Epoxy is insulating.

Rob

[cliff park]

Have you tried filing the end of the brush dead flat, ie so it is not concave. A smooth file should do it, but gently, carbon is soft. It should still make enough contact to run the motor, and then bed back in. Also check for end float of the shaft to make sure that the thrust is not pushing it along so that the ends of the windings are touching the brushes. 

[StrathpefferJunction]

Thanks, folks. Some good suggestions. I'll take a further look this week. Much appreciated. 

[stewartingram]

I'm sure you will have done this already, but have you disconnected the gears to elimate those? Easily done of course, by removing the metal clip on the back of the motor. Also, has somebody cleaned out the commutator slots, and left a burr on the edge of the copper? Might also be worth removing the faceplate (don't lose the springs & brushes) and checking for an obstruction - I even found a track pin in there once when repairing a customer's loco!

 

Stewart

[StrathpefferJunction]

Hi Stewart. Many thanks indeed for the input. I have stripped it down completely and run it with only the drive gear in place; no difference. If you spin the motor by hand, you can hear the click. Remove the brushes, no click. I have looked at the gab between the commutator pads, but nothing looks rough. The only thing that I can see is a slight warping of the commutator - very slight - but it seems to coincide with where on the rotation of the armature the clicking noise occurs. I'm not sure if it's phenolic material that's under the copper, but whatever it is, I think it may be the culprit. Never come across this particular issue before and I've looked at quite a lot of these in my time. Had me stumped!