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