# LGB 20670 Track Cleaning Loco



## gramps (Dec 27, 2007)

Hi,

I have a problem with my LGB track cleaner (1993 vintage). A few months back I had to replace the original motor because the brushes had worn down completely and new brushes are not available here in the UK. The new motor lasted just a few hours of running time before it seized up.

Fitted a new motor again today and after just one hour the same thing happened. Motor too hot to touch and the shaft seized.

My first thought was a faulty motor, but as it has happened twice there must be some problem with the loco itself.

Any thoughts?

Appreciate your help.


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## ntpntpntp (Jan 14, 2008)

Are you referring to the main chassis block motor or the motor for the cleaning wheels?


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## gramps (Dec 27, 2007)

Hi,

the cleaning motor.


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## Dan Pierce (Jan 2, 2008)

There is a thermal sensor on the cleaning motor, is it still in place inside the motor block?
With the motor removed do the wheels turn freely? On my TCL the wheels do turn easy by hand even when assembled.


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## gramps (Dec 27, 2007)

Dan Pierce said:


> There is a thermal sensor on the cleaning motor, is it still in place inside the motor block?
> With the motor removed do the wheels turn freely? On my TCL the wheels do turn easy by hand even when assembled.


Hi Dan,

Thanks for your response. To answer your questions in reverse order:

Yes, the wheels turn freely with the motor removed.

There is a small lozenge-shaped component in the wiring to the motor. I assume this is the sensor. But it is outside the plastic motor box. Should it be inside?


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## Dan Pierce (Jan 2, 2008)

It can be the motor itself is bad, they can overheat after awhile and cause a current overload and sometimes the bushings wear and cause binding.
Make sure the motor has no shaft movement to the outside casing in any direction, and a slight in and out movement is OK.


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## gramps (Dec 27, 2007)

Two bad motors in succession seems unlikely. Both have seized up so that the shaft can only be turned by hand with great effort. I'm thinking some sort of meltdown inside but what is likely to cause this?


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## Michael Glavin (Jan 2, 2009)

Was an OEM LGB motor used as a replacement?


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## Greg Elmassian (Jan 3, 2008)

To summarize:

1. who replaced the motor?
2. is it an LGB motor, the exact replacement?
3. It seems that the temp sensor was supposed to be inside, is this true, did the repair move this outside the motor block?
4. what power supply are you using and what voltage do you run this at?
5. Just before burning up, did the unit work properly, i.e. did it run just as fast as the original at the same "speed setting" on your power supply.

Something has changed.

Greg


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## gramps (Dec 27, 2007)

Hi Guys,

thanks for your responses. To answer Greg's questions:

1. me.
2. it's a Buhler motor identical to the original except that it is a sealed unit (you cannot open it to replace the bushes).
3. the sensor is outside the plastic box that houses the motor. I think that's how it was when I dismantled the motor box. Are you saying that it should be inside? - it would be a very tight fit.
4. power supply is a Gaugemaster Series 100 24v 2.5 amp. I did not measure the voltage when running the track cleaner but the control knob was set on 70/100.
5. the unit seemed to be working OK, just like the original.

It looks to me like number 3 may be the answer.


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## Dan Pierce (Jan 2, 2008)

Yes, the sensor should be inside and is a very tight fit.
But this is not your problem as you had 2 motors that did not spin freely, the sensor just stops power from going to the motor if the motor gets hot.
Possibly 2 bad motors in a row, or there is a alignment issue with the motor/axle gear causing binding and the motor to work too hard thus over heat and self destruct as no thermal sensor was on the motor.

After changing the motor did you check to see of the wheels turned freely on the assembled block?


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## gramps (Dec 27, 2007)

Hi Dan,

yes, the wheels turned freely when I fitted the new motor.

It seems to me that the problem must be that I left the sensor outside the box both times (duh!).

But, why does the motor run so hot?


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## stevedenver (Jan 6, 2008)

this may be way too simple, but, have you fully disassembled the cleaning wheels, and looked for bits of hair like shavings that get twisted around the cleaning wheel axel, as well as thoroughly cleaning the carbon/brass dust. you might also visually inspect the worm and axle gears inside the cleaning motor housing.

the cleaning locos need to be frequently and routinely cleaned up. I do this for about every hour of use. excessive?? 

perhaps, but, the plastic flanges of the cleaning wheels which hold the abrasive discs lose a bit of plastic, in the form of fine, hair like threads that find their way to the axel. They are not always easily seen simply looking down onto the axel.

you might check this 'cleaning' aspect if you haven't already. this adds a bit of drag and premature wear as I understand things.


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## Dan Pierce (Jan 2, 2008)

OTOH after more than 10 years I have only changed the cleaning rings/pads on my track cleaner, different people will get different results.


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## Michael Glavin (Jan 2, 2009)

Is the motor a Buhler replacement offered in lieu of the original OEM motor? What I'm getting at is the internal motor winding package maybe different, motor physical shape and size is only halve the equation.

I don't recall on my track grinder where the aforementioned temperature sensor is located but it makes sense it would be within the motor box adjacent the can motors exterior shell.

Michael


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## gramps (Dec 27, 2007)

Hi Guys,

The wheels etc. all move freely - it's the new motors that have seized up.

The original motor was also a Buhler. This still spins freely but the brushes are worn down completely so it will not run when I apply dc power.

It seems impossible to obtain new brushes for the original motor. All that is available here in the UK is a replacement Buhler motor which is a sealed unit.

I wish I could get to the bottom of this problem.


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## Gary Armitstead (Jan 2, 2008)

gramps said:


> Hi Guys,
> 
> The wheels etc. all move freely - it's the new motors that have seized up.
> 
> ...


I have a question regarding the brushes on your original Buhler motor (the one with the worn brushes). Can you get to those brushes to check the physical size of the brush? Or how it is connected to the motor? Are you able to remove the new brushes from the seized motors to get a physical size of the brush?

Motor brushes come in all sizes and capacities. As an example, we purchased some new, but surplus motors 24 volt DC for a 1/8 scale electric engine. We worn out some brushes on these motors and started to look for replacements. We had no name for a manufacturer on them. A couple of the motors had model numbers. We did not know the length of the original brushes because they were worn, but we DID know the diameter. Did some searches on the internet and found brushes designed for the voltage and amps required. Almost ALL brushes come in standard lengths and width or diameter. Buhler is a well known name in electric motors. This shouldn't be this difficult to hunt down. You have to think a "little outside the Red Box". If I could find brushes to fit an obscure surplus motor with NO manufacturer name, I am sure you can find them for your old motor. I have a friend who has one of these engines and I will check with him. Maybe we can get some useful information for you to get this fixed. It's definitely not rocket science.


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## gramps (Dec 27, 2007)

Hi Gary,

That is something I hadn't thought about. Perhaps I could dismantle the new motor and extract the brushes. I'll have a look tomorrow - it's nearly bedtime here.

Thanks.


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## Gary Armitstead (Jan 2, 2008)

gramps said:


> Hi Gary,
> 
> That is something I hadn't thought about. Perhaps I could dismantle the new motor and extract the brushes. I'll have a look tomorrow - it's nearly bedtime here.
> 
> Thanks.


Try removing the worn brushes from the first original motor. That will tell you the diameter/rectangular size of the original brush. The new motor brushes will also get you the length you will need. Then replace the worn brushes in your old motor. If it worked at one time, then it should work now with the new brushes. Seems simple to me.


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## Dan Pierce (Jan 2, 2008)

If I remember correctly, there is a small spring putting pressure on the motor brush, but the real electrical contact is a braided wire which is molded in the brush and spot welded to the brass housing/plate.


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## gramps (Dec 27, 2007)

HI Guys,

Impossible to dismantle the new motor without dynamite!

But I will try to find replacements for the original brushes on the web.

Thanks.


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