Hornby Dublo Ringfield, bearing failure

[locomad2]

I've a Hornby Dublo WC fitted with a Ringfield motor which I've had from mid 1960's, unfortunately over the last 25 years its been a poor runner, it also had a tendency to come off on curves, most of its live spent in a box.

 

Recently I've tried to fiqure out what the problem was, it recorded free running 1.20 amps @ 12v. A remag was done not easy or successful on Ringfield and got it down to 0.80amps @12v.

 

Even disconnected motor recorded 0.75amps at 12v, it also seemed to vibrate, i suspected bottom bearing next to worm often the bearing gets lost or rusted up as only about 1mm in diameter. On stripdown using a magnifying glass could see bearing stuck to one side as if its drilled itself sidewards, the armature had burring on the end as you getting on pin punches.

 

Quick fix was to put in a new bearing and deburr the armture shaft and try it out, instant success motor run at 0.25amps @12v, only slight hitch the top bearing mount now sticks out.

 

 

 

It's been running like a dream easy pulling 9 Hornby Dublo coaches, and under the bible guide of 0.65amps @12v.

 

How it happened manufacturing fault or careless maintenance years ago prehaps screwing down too hard the top bearing ?

[34theletterbetweenB&D]

I would suspect run 'dry'. Lack of lubrication produces the effects you describe. A tiny dab of light oil on the motor shaft bearings every running session will limit wear.

 

(Bought a few cheap 'non-runner' 8f's for the bodies and a couple had motors worn like this. likewise had a look at a few other ringfield powered H-D in similar condition. That's the trouble with all that motor power, with sufficient current it keeps going, despite the friction...)

[DCB]

It sounds a bit odd that the bearing mount is so far out, I'm guessing the new bearing(s) is/ are larger than the originals.      Well done recovering the damaged armature end.      I always thought the armature shafts had dimples in the ends, that may have been wear I suppose.
To be honest of 12 Ring Fields, 2 x R/B WC  4 x Castle, 3 x 8F 2 X 08 and a castle powered 56XX (!)  I have never had this issue.  The bottom bearing housing has distorted on some vertical rectangular magnet as the ball has driven deep into it by over tightening and the sides of the same bearings have worn where the bearings have been left loose. My Ringfields have however needed frequent dismantling and oiling and a build up of gunge inside the magnet which drags on the armature.  Apart from the 60:1 Romford geared 08 and the Triang geared 56XX  I have found the Ring Fields heavy on maintenance needing far more than  X04 or H/D 1/2" motors, I work them hard at low speeds and  revs long trains and steep grades which makes them heat up, but apart from oil they seldom need any thing other than a clean and adjust the bearings.    The whole H/D range is very reliable in my experience.  

[locomad2]

Found another "Ringfield " motor which for years was known to be "rough" on a another HD 8F 2 rail, however years ago the motor switched to a 3 rail one and not used much since then

 

Higher ampage 0.7amp, vibration running on its own, poor starting, originally the motor had a high usage on childhood layout, again its possible over tighting magnet end screw,  lack of lubricants  or even gumming up of oil (peco electro lub used on mosy locos in 70's)

 

 

Diagram 1 i reckon what it should look like end of shaft steel shaft in brass block with bearing at end,

 

Diagram 2 is what gone wrong, bearing pushed out of place as much as shaft passed it and in a void

 

Diagram 3 is the "2 bearing fix", simple and easy 

 

Result on second "Ringfield" instant, ampage down to 0.2 free no vibration, i also leave more play in armture.

 

I agree with above comments Ringfields v's 1/2" motors over time, 1/2" been more reliable, look better easier to remag and better weight distribution over chassis ( too back heavy). However ive still got 1/2 dozen or so to keep running

 

[Pebbles]

Do Scale Speed still do a replacement motor for the Ringfield? It may have been called "Cab Free" or something.