Poor running motor

[Sophia NSE]

I have a motor, I believe to be a K's one though I could be wrong, that runs for about 10-15 seconds now before slowly coming to a halt 

Is it better to try and get it working again or get a replacement motor?

[AndyID]

Yes, it's a K's. You could try a tiny drop of oil on the shafts close to the bearings. It might be suffering from lack of lubrication.

 

There is something odd about the shaft at the worm end. I don't know what's going on there.

[skipepsi]

I would replace it. 

[Sophia NSE]

19 minutes ago, AndyID said:

Yes, it's a K's. You could try a tiny drop of oil on the shafts close to the bearings. It might be suffering from lack of lubrication.

 

There is something odd about the shaft at the worm end. I don't know what's going on there.

Yeah, part of the shaft appears to be on a screwhead, but it does still rotate

[AdamsRadial]

You say it runs for 10-15 seconds, I assume that is enough for the worm-wheel to make at least a complete revolution? I've had an old loco once that had bent teeth on the worm wheel so that it would only turn through about 300 degrees before stopping.

 

When it comes to a stop is it humming or buzzing, or just silent? If the former then it suggests friction or tightening up, if the latter it suggests loss of electrical connectivity.

 

For the former, the advice to lubricate is good, I would also suggest you check parts of the chassis such as the axle bearings and the con-rod pins in case they are also stiffening up.

 

For the latter, there are two possible causes. The first is the brushes losing connection with the commutator, the second is the pickups losing contact with the wheels. Spraying the commutator and brushes with switch-cleaner will help a bit, likewise spraying the backs of the wheels where the pickups touch them will also help.

 

Personally, I think it looks too nice to bin

Edited February 11, 2021 by AdamsRadial

[Sophia NSE]

It just goes completely quiet and the time is more than enough for several revolutions of the worm wheel. I didn't build the chassis so I'll have to have a look at it.

 

What would be recommended for lubrication purposes?

[AdamsRadial]

Watch oil or Clock oil for lubrication.

 

When it goes quiet, is the armature or any part of the brush gear warm to the touch? If you flick the armature does it give any feeling of resistance?

Edited February 12, 2021 by AdamsRadial

[Pebbles]

Remove both brushes - the holders are simply push fit - and ensure that the brushes are free to move within the holders and the brush spring are doing their job. Clean both brushes and the holders; reassemble and test before reinstalling the motor.

[hayfield]

The front bearing looks to be extended out of the block

[AndyID]

8 hours ago, hayfield said:

The front bearing looks to be extended out of the block

Is that a spring between the bearing and the worm?

[Izzy]

Could it be that the front bearing has worked itself out of the magnet allowing the commutator under any kind of load to jam up against it? I am presuming the spring is a thrust washer arrangement to stop the armature slopping back and forth under load and direction. Should be possible to push it back into place if so and retain with a bit of cryno.

[DCB]

Definitely looks like the front bearing has worked itself out/ forward, possibly until it hit the nut.

Needs shoving back in.  Dollop of super glue etc.

Be very careful removing brushes, the little beggars are spring loaded and love to fly across the room. The springs however can get soggy and that slows the motor . The K's  motors are quite nice, bit gutless compared to a Triang X04, but very smooth and difficult to replace with modern equivalents due to their length.  I used one to replace Anchoridge motors in my K's  28XX after someone had upgraded it with a Comet chassis etc.

  If you replace your motor stick it on eBay and I'll be bidding on it.   I want one for a 14XX, 50:1 gears on the driving wheels and 40:1 on the trailing wheels sort of an 0-4-2-0 with 6 wheel drive....