LGB Track cleaner thermal switch

[Airbuspilot]

Does any one have any experience of the thermal switch fitted in the motor block on the LGB the track cleaner?

I changed the cleaning wheels and have had problems running since the change. In a previous post I reported a possible short circuit when in cleaning mode. The loco drives normally forward and back but when cleaning selected with speed slider at zero the cab roof lights flash and head lights are ON. Moving the slider caused what looks like a short, all lights OFF and Loco is dead for about 10 seconds when it recovers with slider at zero.

I have removed the motor block and taken it apart, the bearings for the cleaning wheel shaft have been cleaned and are running freely. The motor block reassembled and refitted. On the bench it ran correctly, on the track it ran well for about 3 to 4 minutes then the "short" occurred again. After a minute or so it again runs normally then "shorts".

When I reassembled the motor block the motor shaft bevel gear looks to be (very) slightly out of alignment with the wheel drive shaft, both motor and wheel bearings are in their correct position and the wheels and motor turn freely so I don't believe its jamming.

The only thing I can think of would which could be a cause would be the thermal switch, however this is in series with the motor and would presumably just stop the motor operation I don't see how it would produce an effect like a short?

I will take the thermal switch out of the circuit and try with just the motor connected to see if that solves the problem. If luck is on my side and this does solve the problem where can I find a replacement thermal switch? I don't see a reference on any LGB paperwork.

Robin

 

[PhilP]

I would not run it without the thermal fuse! - If the thermal fuse is cutting out, then recovering, it is protecting the rest of the electronics..

I have had to replace the electronics on many of these, and it is normally plastic 'stringing' around the cleaning axles, and /or, a contaminated cleaning motor..

If you can run it with the covers off, you can quickly 'touch and let go' the thermal cutout. - If it has 'blown' it will be HOT.

Either this thermal cutout, or the decoder itself, would appear to be shutting down.
You need to work out if it is total current (so decoder) or cleaning motor / driver circuitry.

PhilP

 

[PhilP]

Hint:
Does your CS show how much current is being used?

Note base-line current. - Nothing running.
Current with track cleaner running round the track. - No cleaning motor.
Current running round the track. - With cleaning motor running.

PhilP

 

[Airbuspilot]

Hint:
Does your CS show how much current is being used?

Note base-line current. - Nothing running.
Current with track cleaner running round the track. - No cleaning motor.
Current running round the track. - With cleaning motor running.

PhilP

Hi Phil

Thanks for your answers. We have a ZIMO MX 10 so yes I can check the current, good idea, I will try to go over again in the next few days, it’s getting very hot at this time of year so my enthusiasm reduces as the temperature rises during the morning.

Do you know a source for a replacement switch? LGB spare parts for this loco doesn’t show one.

Robin

 

[PhilP]

Hi Phil

Thanks for your answers. We have a ZIMO MX 10 so yes I can check the current, good idea, I will try to go over again in the next few days, it’s getting very hot at this time of year so my enthusiasm reduces as the temperature rises during the morning.

Do you know a source for a replacement switch? LGB spare parts for this loco doesn’t show one.

Robin

By 'switch' if you mean the thermal fuse, then I have a 2Amp version for 65p.

You can Googley for 30V 2A Polyswitch, and see if anything comes up more local to you.

But the Polyswitch is a protection device, and I doubt it is the problem.

My guess would be the cleaning motor has stalled at some point, and got hot, and possibly swelled a little?
When it is working hard, the windings heat up and expand. Possibly enough to catch on the inside of the motor housing. This creates friction (more heat) and the motor draws more current..
Eventually, either the Polyswitch cuts out, or the rest of the decoder gets hot (or reaches an internal limit) so shuts down..
Everything cools down, so it resets, and will then run again.

PhilP

 

[Airbuspilot]

By 'switch' if you mean the thermal fuse, then I have a 2Amp version for 65p.

You can Googley for 30V 2A Polyswitch, and see if anything comes up more local to you.

But the Polyswitch is a protection device, and I doubt it is the problem.

My guess would be the cleaning motor has stalled at some point, and got hot, and possibly swelled a little?
When it is working hard, the windings heat up and expand. Possibly enough to catch on the inside of the motor housing. This creates friction (more heat) and the motor draws more current..
Eventually, either the Polyswitch cuts out, or the rest of the decoder gets hot (or reaches an internal limit) so shuts down..
Everything cools down, so it resets, and will then run again.

PhilP

I am not sure how old this Loco is but it has been used frequently by us so the possibility of a faulty motor makes sense. Initially the unit died immediately when the motor tried to run which would account for a "short" reaction from the decoder if the motor was stuck. I will try the current check over the next few days and will probably change the motor which is probably getting old and due for replacement anyway.

Robin