> Hornby HST with Ringfield Motor - can I swap the motor or bogie as it is a 'lumpy' runner

[Art Dent]

Hi folks,

I hope that some of you on the forum can help with this.

My son picked up a s/hand Class 43 (aka Inter City 125 HST) and would like to run it on DCC. This isn't a DCC question, so please bear with me.

It ran 'fairly' well and seemed to improve in terms of speed and running as time went on.

I took the motor out (a 3-pole Ringfield type 1) and dismantled it, cleaning the commutator, filing the brush surfaces flat and cleaning the brushes and brush springs. The bearings and gears (horrid, horrid plactic affairs) were then lightly oiled and the collecting surfaces of the wheels cleaned. It then ran very well but was still VERY lumpy at low speed - due I'm sure to the 3-pole armature.

As it was running fine now (apart from at walking pace) I fitted a Zimo MX630 decoder after checking the current draw of the motor (0.28A at max speed, 0.42A when stalled) was well within the MX630's 0.75A continuous current rating. This was a doddle to do as both brush contacts were isolated from the metal chassis of the bogie (= Ringfield Type 1?).

It runs fine on DCC - except at low speed where it still remains very lumpy. It will crawl at speed step 1/128, gets noticeably smother around speed step 9/128 but only really gets anything like smooth around speed step 60/128.

I have a few questions.

1) Do you think that the 'lumpyness' would be partially corrected by removing the capacitor that is soldered between the two silver 'U'-shaped brush contacts?

2) The Ringfield motor is an absolute dog - at least in this 3-pole version. Are 5-pole Ringfield motors available and, more to the point, if there are, are they any better??

3) Could a different motor be easily fitted to the Hornby bogies - I'm thinking a 5-pole can-type (Mashima??) I'm thinking this would be a huge modification undertaking as it would have to rely on Hornby's track pick-up arrangement (which is also an absolute dog).

4) Are there replacement bogies c/w motor and all-wheel pickup available - I'm thinking that there would be. If anyone knows of a source for these and could provide a link, I'd be most grateful.

5) Ideally I feel that an overall better solution would be a centrally-mounted can-type motor with balance weights/flywheels and cardan shafts going to replacement bogies with worm drive/gear towers at both ends of the power car would perhaps be the best way to go. Again, does anyone know if these are available and if so, a link for these too would be great.

In the meantime, I'm Googling to see what I can find.

Thanks folks,

Over to you ...

Art

[DCB]

Its the combination of coarse spur gear final drive and traction tyres causing the lumpiness, changing the armature would have a negligible effect though on DC a bigger capacitor would be a useful experiment as would changing the wheels to something without traction tyres.

 

Optimum is probably as you say big motor/ flywheel, probably better to power the blunt end bogie on both power cars and add plenty of weight, the blunt end wheels spinning are so much less noticable than the sharp end ones.