Motor in metal GWR (Dean 3000g?) tender - advice needed to identify and service.

[DK123GWR]

Long ago I had a City of Truro given to me. The locomotive is plastic, presumably an Airfix/Dapol kit, and is propelled by a metal tender, which is a poor runner. There are a few issues with it: the pickups need tweaking (and more need adding), the gear train needs to be cleaned and lubricated, and the commutator needs cleaning too. Usually, this means that the motor brushes would also benefit from being cleaned. However, the motor does not appear to allow access to the brushes. Based on the images below, can anybody identify the motor and confirm whether there is a way to access the brushes. I have also included a photo of the chassis undertray, which appears to have branding on it (though searches for "A K's model City of Truro" and similar have yielded nothing so far).

 

As a further question: the motor is currently held together by the shaft only. The top part of the casing (including the part at the non-commutator end) are currently free to pivot and to slide backwards and forwards on the shaft. Since the tender body screws into the top of the motor casing, the body is free to move in relation to the chassis (and often ends up sat at an unusual angle). Is this supposed to be the case? What appear to be glue marks on the motor casing at the commutator end could suggest not. Thanks in advance for any advice on maintaining this mechanism.

[kevinlms]

It's a K's tender drive.

 

He's one of a number of threads on it! There just might be better options.

 

 

[AndyID]

Yes, it's K's. The top and bottom pole pieces are not aligned correctly. The brush holders should be in line with each other.

[D51]

Kevin is quite correct, the locomotive has been motorised using a K's tender drive unit.  In the K's motor the magnets are the two blocks holding the bearings and these are held by epoxy-resin glue to the steel pole pieces which transfer the magnetic field to the motor armature.

 

What has happened here is that the glue holding one of the magnets has broken down and no longer holds the thing together.  The previous owner has tried gluing this together again, hence the glue marks, but this has not been successful.

 

The carbon brushes are retained by the brush caps which also attach the tags which have connected to the pickups.  The whole mechanism has unfortunately been taken apart.

 

The K's tender drive unit was, in my opinion, quite a good idea in its day although the gears were usually very noisy.  If the motor was overloaded it would get hot, very hot, and this would break down the glue holding it together.  Repairing this was not practical.

 

I have half-a-dozen of these tender drive units used for all sorts of purposes.  George E. Mellor used them in his narrow-gauge locomotives.  They last quite well provided they never get too hot!

 

Once the magnets have been separated from the steel pole pieces they lose their magnetism so need to be remagnetised.

I think you will probably have to start from scratch with a new modern motor unit if you can find one.

 

Frank

[DCB]

The brush holders just push in to insulated bushes in the pole pieces .  The motor has effectively come apart at the seams, it can be super glued back together but fixing it more securely with some bracketry may be a better alternative.     They are pretty awful as tender drive units, smooth but gutless they make reasonable loco chassis and are excellent tender motors for driving loco wheels through drive shafts.

However personally I would shorten the armature and use it in an X04 or H/D 1/2" Motor