The LNER Encyclopedia

Ay up!

I reckon quite a few folks reading this have old Mainline split chassis locos with the old pancake motors. I have. To wit, 1 Rebuilt Scot, 1 Rebuilt Patriot, 1 P/B Scot, 1 Collett Goods and 1 J72. Previously when these have played up, I have removed the motor faceplate and cleaned the commutator before reassembling.

While running the J72 in before a running session, this showed the usual symptoms of a clogged commute. Being a little engine and being low on paitience (situation normal then!) I decided to put power direct to the brush spring retainers. Perfect running. Power to chassis halves. Nowt. Further experimentation revealed one half was passing power to the motor but the other wasn't. I undid the screws on the faceplate by two or three turns, keeping pressure on the brush retainer plate then tightened them. Result! One smooth(ish) running Mainline loco! The same trick has worked on the rest.

Try it - you may resurrect an old favourite without much effort.

Oh, and a drop or two of oil on the bearings never goes amiss either. Just the merest trave though on the bearing in the middle of the motor faceplate. We don't want oil on the commute!

BB wrote "Oh, and a drop or two of oil on the bearings never goes amiss either. Just the merest trave though on the bearing in the middle of the motor faceplate. We don't want oil on the commute!"

Now whats a drop of oil???????????????

Answers later!

What's a drop in SI units?

according to Wikipedia, a drop is 1/288 fl oz;
OR in medical terms 1/12 ml;
OR in metric 1/20ml;
OR in the States there's three alternatives, 1/360 US fl oz, 1/456 US fl oz or 1/576 US fl oz. I suppose in the States, it depends if you're buying or selling.

http://en.wikipedia.org/wiki/Conversion_of_units

Ay up!

I define it as a small bead on the end of a pin. Make of that what you will.

There's always a clever dick!

Oil is not WD40

Ay up, Bill!

You are 100% correct in what you say. WD40 will dry and seize the loco solid. I've had a couple of those in for repair recently....

However, the Collett goods (Mainline) that has had the treatment described above proved to be a good little runner last night, as did the Dapol County and the Hornby TD 28xxs, though these last two climbed all over the handbuilt points on Charwelton! Hmmm. Where's them Mainline Scots of mine?

Ay up!

Tried this fix on a Mainline Scot that hasn't even been out of its box for at least two years. Went from no movement to smooth (ish) running.

10 years and this thread is still helping , thanks

The construction of the electrical circuit on these products was typically by pressed metal pieces screwed onto the chassis block halves, which then made a surface contact with the brush retainers. It only needs a little oxidation on a contacting metal surface to significantly limit conduction. Disturbing the motor construction as described in the OP, has the indirect effect of temporarily restoring conduction. As ever, replacement with a soldered connection eliminates this trouble.

I am having problems with a split chassis Mainline Collett Goods loco which appears to be 'dead'. I have stripped it down to the bare chassis and removed the faceplate by removing the brush retaining plates. I have applied power directly to the commutator and the motor runs fine but when I refit the faceplate (without the screws and brush assemblies) and simply insert the power leads through the holes in the faceplate where the brushes should be and these make contact with the commutator the overload/short circuit button on the controller is activated. I have checked that the commutator will rotate freely in the bearing in the face plate by removing it from the chassis.
Any suggestions would be welcomed.

I suspect that poking wires though the motor faceplate is the problem, no way can you be sure that the bare wire ends are stable and solely where they need to be on the commutator segments while it is rotating; thus the short circuits.

You have established that the motor potentially runs, your best move is to reassemble the brushes so that they are the current path to the commutator, and test the running at that stage, and if that works, then complete the reassembly, testing at each stage.