Understanding electrical connectivity on 0-6-0 diesel shunter

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SquiddlyDiddly - 25 Jun 2006 08:41 GMT

I have a diesel shunter from the 80's / 90's that has lain idle for a
long time. When I came to get it working it didn't.

It is powered by one of the small motors with non-replaceable brushes
held in a wiring harness.

I have taken the motor out and it works. I put the motor back in the
harness and it still works so it is just when I apply power to the
wheels that it shorts.

I have two questions I suppose.

1) How does power get from the right hand side wheels to the top of the
wiring harness as there is no coonection between the pickup strip and
the top of the harness?

2) The wheel sets move quite a lot and when they touch the chassis side
they connect across causing a short. Should there be some insulation
washers on the axles?

Any help would be most appreciated.

Andy Kaye

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Ian J. - 25 Jun 2006 09:09 GMT

>I have a diesel shunter from the 80's / 90's that has lain idle for a
> long time. When I came to get it working it didn't.
[quoted text clipped - 19 lines]
>
> Andy Kaye

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

Ian J.

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peter abraham - 25 Jun 2006 16:37 GMT

>I have a diesel shunter from the 80's / 90's that has lain idle for a
>long time. When I came to get it working it didn't.
[quoted text clipped - 19 lines]
>
>Andy Kaye

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.

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SquiddlyDiddly - 26 Jun 2006 16:10 GMT

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

> >I have a diesel shunter from the 80's / 90's that has lain idle for a
> >long time. When I came to get it working it didn't.
[quoted text clipped - 38 lines]
>
> Regards P.A.

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simon - 26 Jun 2006 23:21 GMT

> Peter,
>
[quoted text clipped - 16 lines]
>
> Andy

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

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peter abraham - 27 Jun 2006 07:47 GMT

>> Peter,
>>
[quoted text clipped - 19 lines]
>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.

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Model Forum / General / Railroads / June 2006

Understanding electrical connectivity on 0-6-0 diesel shunter