Farish can motors...problems in the future??

[DesertHound]

It's ok Caz - found Belstone's blog 

A link would save others looking.      

Wouldn't want to hijack the thread Caz  oh go on then ... here you are ...

http://belstone9mm.blogspot.ae

I don't think it goes into detail about the Hanazono motors but I'll encourage Belstone to get a thread going and we'll rightly keep this one for what its title implies it's about.

Cheers

[DesertHound]

Hi all,
Just thought I'd share this with you. A week or so ago my Graham Farish class 47 'Hadrian' loco failed, it ran a circuit of the track then suddenly slowed down & stopped, the lights still worked but it wouldn't run. So I stripped it down, tested the motor & it would barely turn, luckily I had a spare secondhand motor, put that in & the 47 is back up & running...

Out of curiosity i had a go stripping down the faulty motor, managed to remove the flywheels with a puller, then opened up the casing & lots of bits of solder fell out. I found that a disc/ring had become detatched from the armature which has obviously caused the failure. Also noticed the commutator has quite a bit of wear, the brushes didn't seem all that worn, this is from a loco that I bought 3-4 years ago & has done about 20-30 hours running max on a 4x2 layout...





All a bit worrying really, I'm wondering if this is going to become a common problem as locos start racking up the hours or whether its just a one off....

cheers, Stu.

Stu

It looks to me as though the suppressor ring might of detached itself and then "collared" the commutator, wearing it down with each rotation. As Russell said, the motor will still run without this suppressor ring, hence why you might not have noticed the problem earlier. Was there any untoward sound when you ran it, prior to it stopping completely?

Dan

[RussellH]

The ring that became detached seems to serve no great purpose - I've seen this on several locos, it's common on early Union Mills steam locos which use a very similar type of motor. The rings do cause all sorts of damage if they become detached, but this usually only happens if the motor gets very hot, enough that the solder softens as others have said. I think ultrasonic cleaning may be an option to clean can motors and their commutators without having to disassemble them, but have yet to try this.

Cheers,
Alan

A bit of reading from the experts....

http://www.precisionmicrodrives.com/tech-blog/2011/06/06/a-short-illustrated-primer-on-brushed-dc-motors

Its in place of "the capacitor" to reduce interference.

Sorry to hear its already binned Stu.

Regards
Russ

[Dr Al]

Useful to know that essentially it has no real effect on the performance as I've seen in those that have been able to be saved after it has come away and been discarded.

I suspect it's a consequence rather than a cause here, but that's impossible to confirm with these can motors where your visibility is totally restricted until you pull it fully apart.

Cheers
Alan

[mk1gtstu]

Hi all,
Just thought I'd share this with you. A week or so ago my Graham Farish class 47 'Hadrian' loco failed, it ran a circuit of the track then suddenly slowed down & stopped, the lights still worked but it wouldn't run. So I stripped it down, tested the motor & it would barely turn, luckily I had a spare secondhand motor, put that in & the 47 is back up & running...

Out of curiosity i had a go stripping down the faulty motor, managed to remove the flywheels with a puller, then opened up the casing & lots of bits of solder fell out. I found that a disc/ring had become detatched from the armature which has obviously caused the failure. Also noticed the commutator has quite a bit of wear, the brushes didn't seem all that worn, this is from a loco that I bought 3-4 years ago & has done about 20-30 hours running max on a 4x2 layout...





All a bit worrying really, I'm wondering if this is going to become a common problem as locos start racking up the hours or whether its just a one off....

cheers, Stu.

Stu

It looks to me as though the suppressor ring might of detached itself and then "collared" the commutator, wearing it down with each rotation. As Russell said, the motor will still run without this suppressor ring, hence why you might not have noticed the problem earlier. Was there any untoward sound when you ran it, prior to it stopping completely?

Dan

No, it ran normally with no nasty noises then just slowed down to a stop & that was it, it would no longer move under its own power. It was a good smooth runner prior to this, it just failed with no warning.
I would have thought the supressor ring was still attatched until the last minute as the amount of lumps of solder floating about in the motor casing would have caused bad running/noises or seizing up long before this happened. I'm more inclined to think the commutator wear is down to brushes being too hard or springs too strong  but as Al says you can't see whats going on inside these motors until you pull them apart.

cheers, Stu.

[Dr Al]

No, it ran normally with no nasty noises then just slowed down to a stop & that was it, it would no longer move under its own power. It was a good smooth runner prior to this, it just failed with no warning.
I would have thought the supressor ring was still attatched until the last minute as the amount of lumps of solder floating about in the motor casing would have caused bad running/noises or seizing up long before this happened. I'm more inclined to think the commutator wear is down to brushes being too hard or springs too strong  but as Al says you can't see whats going on inside these motors until you pull them apart.

cheers, Stu.

Seems likely that the failure mode was either the commutator becoming clogged up, semi-shorting and heating up the motor to the point that the ring detached and damaged the windings, killing the motor (Was there brush carbon in the commutator, or any evidence of clogging up of the commutator?); or the ring itself coming off first hand and detaching the wiring to the comm. I would suspect the former, if it ran slow first this is a classic case where the motor will get hot (less back emf generated by the slow running, so the motor will pull more current, and the energy dissipated goes as the square of the current, hence heating can go up a lot for small current increases).

It's perhaps too late, but you should save the motor end cap with it's brushes - it might be a useful spare for other models if/when brushes in them wear down (assuming they don't die in this way first).

I would urge you to contact Bachmann and make them aware also.

Best,
Alan

[Dr Al]

P.s. it's worth investing in a moving coil ammeter, and wiring this to your layout - this can help spot problems before they become terminal - e.g. in this case it would probably have identified a high current draw from the motor prior to complete failure. Very useful for troubleshooting.

[mk1gtstu]

No, it ran normally with no nasty noises then just slowed down to a stop & that was it, it would no longer move under its own power. It was a good smooth runner prior to this, it just failed with no warning.
I would have thought the supressor ring was still attatched until the last minute as the amount of lumps of solder floating about in the motor casing would have caused bad running/noises or seizing up long before this happened. I'm more inclined to think the commutator wear is down to brushes being too hard or springs too strong  but as Al says you can't see whats going on inside these motors until you pull them apart.

cheers, Stu.

Seems likely that the failure mode was either the commutator becoming clogged up, semi-shorting and heating up the motor to the point that the ring detached and damaged the windings, killing the motor (Was there brush carbon in the commutator, or any evidence of clogging up of the commutator?); or the ring itself coming off first hand and detaching the wiring to the comm. I would suspect the former, if it ran slow first this is a classic case where the motor will get hot (less back emf generated by the slow running, so the motor will pull more current, and the energy dissipated goes as the square of the current, hence heating can go up a lot for small current increases).

It's perhaps too late, but you should save the motor end cap with it's brushes - it might be a useful spare for other models if/when brushes in them wear down (assuming they don't die in this way first).

I would urge you to contact Bachmann and make them aware also.

Best,
Alan

There was a bit of carbon around the commutator, I did save the end cap & brushes, just binned the bits that were no good.

cheers, Stu.

[belstone]

Thanks to all who have expressed an interest in the Farish motor conversions.  Sadly this was around 10 or 12 years ago and I cannot find any photos of the conversions although I thought I had taken some.  Basically it involved cutting the top section out of the chassis block above the old motor and replacing it with a brass plate to bridge the gap, which provided enough space for an open frame 5 pole with the shafts going through the bearing blocks from the original Farish motor.  The motor itself was free-floating in the chassis, with just a couple of tabs to stop it trying to rotate under load. Ideal for DCC conversion as both motor brushes are insulated from the chassis.

Richard

[Dr Al]

Sounds much the same as this:

http://www.deas.net/littlewood/

Cheers,
Alan

Thanks to all who have expressed an interest in the Farish motor conversions.  Sadly this was around 10 or 12 years ago and I cannot find any photos of the conversions although I thought I had taken some.  Basically it involved cutting the top section out of the chassis block above the old motor and replacing it with a brass plate to bridge the gap, which provided enough space for an open frame 5 pole with the shafts going through the bearing blocks from the original Farish motor.  The motor itself was free-floating in the chassis, with just a couple of tabs to stop it trying to rotate under load. Ideal for DCC conversion as both motor brushes are insulated from the chassis.

Richard