Understanding electrical connectivity on 0-6-0 diesel shunter

Can you tell us the manufacturer of the model, and also the class of locomotive it represents?

Ian J.

One set of wheels are metal to metal onto the axels and are common to the chassis and then to the motor by a short bonding strip of phospher bronze (often under the motor frame and not visible). The other set aremounted onto the axels via insulated inserts and the inner rims rub the contact strip of phospher bronze thus taking the power away to the other motor wire. If the connecting rods can touch the axel pins there will be a short circuit but this is unlikely.However, if your wheels are insulated between the rim and the spoked section then this is possible a cause. If your pick-up strip is distorted and can touch the chassis when the side slack takes up then that will also short out. A modest piece of black insulating tape placed on the chassis section will take care of that. Other wise, have a good look at the "live" flying connection from pick up strip to motor and make sure that it is not nicked and shorting the the chassis or motor. Equally if itis a centre worm drive - make sure that the wheel set is not reversed.

Regards P.A.

Peter,

A very comprehensive reply.

The model is a Horby Class 08 by the way.

Even without the motor or pickup copper present, if I push a wheel into the chassis I can cause the short which indicates that I may need to add an insulated washer between wheel and chassis to keep them from touching. However, the original Hornby Service Sheet doesn't show these.

I don't think the connecting rids are the problem but it could be the pickup strip is touching somewhere. Will try the insulation strip. I will also check that the wheel set hasn't been reversed. Didn't think of that.

Thanks

Andy

peter abraham wrote:

Do many (or even any) Hornby locos have uninsulated wheels ? Simon

I have many such examples where only one side is insulated albeit on older models such as that under discussion - one of which I do have.