Farish worm gear spacing - help needed

Started by Snowwolflair, February 24, 2020, 03:42:43 PM

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Southerngooner

As has been noted before on this forum we run our locos hard on James Street and haven't seen any failures on cordless motors on around 100 locos. I actually prefer taking the new split chassis apart as they are simplicity in itself, except where there is valve gear, which is a problem on older Farish too. It's like Hornby Dublo v modern Hornby, crude and simple or detailed and more modern. You pays your money, you takes your choice.....
Dave

Builder of "Brickmakers Lane" and member of "James Street" operating team.

Fredastaire

@Southerngooner , I can only give my personal thoughts and opinions on what I have stripped and investigated. My opinion is that these coreless motors fail through total accrued lifespan running, the brushes and commutators show to have mechanically failed through being worn out. Ive seen no burnt out armatures, no burnt brushes so my opinion is that it is not a case of 'hard running' overheat damage. Those motors where I have fitted replacement end caps / new brushes are still working now so definitely have not suffered winding burn out.
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Ive also bought a non runner Bachmann coreless from an Ebay seller, with the same bust brushes, so this is clearly from another layout elsewhere in the country, that motor ive rebrushed, it too works, ive tested it in a STD 5 then put it in my bits box for future use.
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I would wish to clearly state that anything ive said is from my hands on dismantling and vieweing thro magnifying glasses. I would welcome others who have stripped faulty Coreless motors to add their post mortem observations.
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Surely one of our members must have experience of a coreless motor post mortem?

Southerngooner

Hi

I am not trying to disagree with your observations, it just seems to me that if Farish were selling something with a 100 hour life motor there would have been lots more problems by now, as that only equates to one hour a week for two years. A lot of locos will have done more than that. Could it be that the problems are a normal failure rate for any batch of product as per the standard distribution curve, in that 5% or so will fail early? If a whole lot of locos were failing (as per the Farish broken gear issue years ago) then it would be more common?

With a replacement motor at around £20 from Bachmann or cheaper from the likes of Tramfabriek then I would rather replace than repair, on the basis that my time is money, but if you can do it and they continue to work well than that's great. I just wouldn't know where to start and I suspect most people would be the same. It's probably very easy to do, but unless you know where to get the parts, what to do and have the skills to do it, then replacement is a safe option.

This has rather taken over a really useful thread on remotoring old Poole stuff, which is a good option for those who wish to continue to run them!
Dave

Builder of "Brickmakers Lane" and member of "James Street" operating team.

jpendle

Quote from: Fredastaire on March 01, 2020, 02:58:41 PM
Surely one of our members must have experience of a coreless motor post mortem?

I have to agree with @RailGooner . I think most of our members, me included, would just replace the whole motor, a post mortem would consist of having a look and a sniff and chucking it in the bin.

But don't get me wrong. I find your threads along with those of @Dr Al and others fascinating. Keep up the good work.

Thanks,

John P
Check out my layout thread.

Contemporary NW (Wigan Wallgate and North Western)

https://www.ngaugeforum.co.uk/SMFN/index.php?topic=39501.msg476247#msg476247

And my Automation Thread

https://www.ngaugeforum.co.uk/SMFN/index.php?topic=52597.msg687934#msg687934

thebrighton

Dragging this back on topic rather than reliability of coreless motors is it possible to add a channel to the print to run the blue wire along rather than having it loose?

ntpntpntp

#35
Just to reply to the thread drift:

Quote from: Fredastaire on March 01, 2020, 02:58:41 PM
Surely one of our members must have experience of a coreless motor post mortem?

Yep. I've replaced two so far in a friend's locos ( a 4CEP and one other multiple unit type which I forget).  I know he certainly doesn't run his models for long periods or under heavy loads.  Post mortem on one of the motors revealed broken brush "fingers". I got that one going again but I wouldn't trust it in a loco now.

As a Continental N modeller I've had a Liliput multiple unit fail and need a replacement motor (they're part of the Bachmann empire too and it's a similar chassis design).

Overall I'm not convinced/happy with this move to smaller limited life motors. The old motors just work and work for decades and can be serviced when needed.
Nick.   2021 celebrating the 25th anniversary of "Königshafen" exhibition layout!
https://www.ngaugeforum.co.uk/SMFN/index.php?topic=50050.0

Dr Al

Quote from: ntpntpntp on March 01, 2020, 05:52:35 PM
Yep. I've replaced two so far in a friend's locos ( a 4CEP and one other multiple unit type which I forget).

No. The 4-CEP is not a coreless motor - it's a 3 pole standard 1015 sized can. No Farish multiple units have coreless motors.

Cheers,
Alan
Quote from: Roy L S
If Dr Al is online he may be able to provide a more comprehensive answer.

"We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces."Dr. Carl Sagan

Dr Al

#37
Quote from: Southerngooner on March 01, 2020, 03:20:58 PM
This has rather taken over a really useful thread on remotoring old Poole stuff, which is a good option for those who wish to continue to run them!

It's highly relevant though, if people are starting to think of wholesale re-motoring - I can see the need at times (if you need a low profile chassis), but one has to balance that with the knowledge that there are real question marks over the longevity of the 0716 coreless motors - relevant when you'll be spending a fair amount to replace a Farish armature that should be able to perform as well.

More data is needed, and I wish Tramfrabriek would have undertaken the longevity test I asked of them a while back.

Despite that, I will be interested to get one of these mounts though - I have a kit tank loco that needs a low profile chassis for it to work. But, I won't be re-motoring everything.

Cheers,
Alan
Quote from: Roy L S
If Dr Al is online he may be able to provide a more comprehensive answer.

"We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces."Dr. Carl Sagan

Snowwolflair

I have been removing material to make the motor mounting as small as is structurally stable.  I am still waiting for the material samples from Shapeways, however even in a brittle resin this new design is strong enough.  My guess the black polished nylon will be ideal.





Snowwolflair


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