[edzmen]

Has anyone done any testing to see how long the new sealed 5-pole motors last? I'm curious to know...
Hornby are quite non-specific and merely state 'after a considerable amount of use', which isn't much help

- where as they used to give a life expectancy in hours with the old Ringfields.

Has anyone done any 'destruction testing' by leaving a 5-pole engine on a rolling road until it packs up?

I'm tempted to try this myself if no one knows, at about £5.00 for a replacement motor it'll hardly break the bank...

 

[Brian Considine]

Don't know about UK outline models but a couple of years ago we tried one of the Piko "Hobby" locos & ran it 24/7. It was pulling 10 coaches on a test layout with a 1 : 50 gradiant, 1 225deg radius 2 followed by a 45deg reverse radius 2 plus assorted other curves & bends, not an easy test. Running at about half speed it ran for just over 3 weeks before the motor brushes gave out. We estimate that it had travelled for almost 300 actual miles.
Good for a loco that retails for around £40 - it's been remotored & runs as good as new.

 

[34C]

Some of the Bachmann cans in their split chassis models have done hundreds of hours: still waiting for one to give up, so I can open it and look inside...

 

[Mike Parkes]

QUOTE (34C @ 25 Nov 2007, 19:57) <{POST_SNAPBACK}>Some of the Bachmann cans in their split chassis models

Bachmann use 3-pole motors

 

[Makemineadouble]

Correction. Bachmann use 3 pole motors in their newer models, the older models with the split frame have the older Buhler 5 pole motor ( well at least the ones I've seen

 

[ozwarrior]

QUOTE (Mike Parkes @ 26 Nov 2007, 07:43) <{POST_SNAPBACK}>Bachmann use 3-pole motors

Which begs the question:

All other things being equal will a 5-pole outlast a 3-pole?

 

[Richard Johnson]

QUOTE (edzmen @ 26 Nov 2007, 02:38) <{POST_SNAPBACK}>Has anyone done any testing to see how long the new sealed 5-pole motors last? I'm curious to know...
Hornby are quite non-specific and merely state 'after a considerable amount of use', which isn't much help

- where as they used to give a life expectancy in hours with the old Ringfields.

Has anyone done any 'destruction testing' by leaving a 5-pole engine on a rolling road until it packs up?

I'm tempted to try this myself if no one knows, at about £5.00 for a replacement motor it'll hardly break the bank...

Motors are generally reliable enough to outlast the locos probable running life.

Older motors were physically robust but had weaknesses in their brushes which were easily damaged by lubricants & wore out and open bearings that needed regular lubrication, plus ferrite magnets that weakened with age... Modern motors look to be less robust but have stronger or better sealed bearings and usually, precious metal brushes that are unlikely to need replacing, plus much better magnet quality. When Hornby first made the change to can motors they mentioned (from memory) 120 hours... However the use is so variable that I don't think its all that relevant anyway

ie:
If you are heavy handed with the oil, or don't lubricate at all it will be much less than whatever the average is.
If you haul heavy trains for long periods or have steeping gradients then heat/cool cycles will be more extreme so it will be much less than whatever the average is.
If you run at slow speed with heavy loads for a long time (heavier current needed so more heating) so it will be much less than whatever the average is.
IF the loco mech is stiff or its jammed with fluff then loads are higher so it will be much less than whatever the average is.

So... if you want to do the test by all means do it - but I don't think it will refect anything than the limits of a motor in loco x when run on a rolling road!

Re 3 and 5 pole - there is no "3 or 5 pole reason" for longer or shorter life - its down to the circumstances its run under and the quality of the materials.

Richard

 

[Brian Considine]

QUOTE (Richard Johnson @ 26 Nov 2007, 02:40) <{POST_SNAPBACK}>Re 3 and 5 pole - there is no "3 or 5 pole reason" for longer or shorter life - its down to the circumstances its run under and the quality of the materials.

I would agree there - a good 3-pole is probably better than a poor five pole.

We run a few Flesichmann locos with the 3-pole motor & fitted with ESU decoders on St.Laurent - they run very, very well & people are surprised to learn that they are indeed 3-pole. As an aside a couple of them are well over 30 years old !

 

[7113]

I read in the instructions for a Hornby terrier that the motor is reckoned to be good for an estimated 150 hours.

Regards

 

[Richard Johnson]

QUOTE (BRITHO @ 26 Nov 2007, 22:22) <{POST_SNAPBACK}>I read in the instructions for a Hornby terrier that the motor is reckoned to be good for an estimated 150 hours.

Regards

*** Not bad actually - Such numbers are reaclly deceptive though - thats a LOT of running!

I have afriend who works for one of the more successful power tool companies, and he told me the re-chargeable batteries in their handyman range were actually rated for only ten hours of use before failure - I was initally taken aback until he made the point that that is a heck of a LOT of drilling and screwing - far more than the average home handyman does in a lifetime, and the option was a far higher priced drill (unlikely to sell well) if the batteries had to be more robust.

Richard
DCCconcepts

 

[ozwarrior]

QUOTE (dbclass50 @ 26 Nov 2007, 19:17) <{POST_SNAPBACK}>I would agree there - a good 3-pole is probably better than a poor five pole.

So why over the last 10-15 years has there been a move to 5-pole?

 

[dwb]

QUOTE So why over the last 10-15 years has there been a move to 5-pole?
Given components of equal quality a five pole motor is preferable to a three pole because there is less "cogging" at slow speed. An electric motor develops its maximum torque when the electric field in a motor coil is at the strongest point of the opposing magnetic field. The repulsive force is less either side of this point. In effect it is like comparing a 3 cylinder engine with a 5 cylinder one. The more cylinders or poles, the smoother the torque delivery. I don't know anything about skew wound coils but I am guessing that these are improvement over straight wound ones in that the electric field has a more even "spread" and so is repulsed by the magnetic field for longer.

Basically the more fields and the more even spread of the repulsive forces results in a more even torque output. It is this desire for an even torque distribution which lies at the heart of the Maerklin Sinus motor design.

David

 

[Brian Considine]

QUOTE (Richard Johnson @ 26 Nov 2007, 14:39) <{POST_SNAPBACK}>the re-chargeable batteries in their handyman range were actually rated for only ten hours of use before failure - I was initally taken aback until he made the point that that is a heck of a LOT of drilling and screwing - far more than the average home handyman does in a lifetime, and the option was a far higher priced drill (unlikely to sell well) if the batteries had to be more robust.
Richard
DCCconcepts

Was that 10 hours or 10 cycles (probably about the same anyway) - could be the reason why the £9.99 18v drill's I bought for the workshop have now expired & the deWalt ones go for ever !

 

[bike2steam]

As for the original question, it begs the answer;- how long is a piece of string.
The life expectancy of a motor depends on both how it's run in, and subsequent use.
A skew wound 10-pole motor SHOULD be more efficient than a straight 3-pole, but if you have the bad luck to have the duff one of the batch all that can change.
Paul M.