Running in a motor?

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cowjam
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Joined: Fri Nov 07, 2014 11:56 am

Running in a motor?

Postby cowjam » Wed Mar 04, 2015 11:40 am

I've heard some people mention running in a new motor, or one that's been in storage a while.

Could someone please describe what this involves and why it's necessary?

Bigmet
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Joined: Tue Aug 14, 2007 2:19 pm

Re: Running in a motor?

Postby Bigmet » Wed Mar 04, 2015 12:27 pm

It is less necessary now with can motors than with the older design open frame types. Many of these latter had no shaping of the graphite brush wipers when new so there was practically line contact to the commutator surface. A couple of hours running at moderate speed and minimal load allowed the graphite to wear a bigger contact patch, so avoiding any risk of localised heating at higher current draw damaging the commutator surface.

It is generally a good idea to run a new model without load at 'half speed' to ensure that lubricant is well distributed through the mechanism - or excess lubricant at any location removed / redistributed, or inadequate / absent lubrication dealt with - and to get all the wiping and rolling contacts nicely polished up for reliable current collection. Most locos will show improvement over the first hour or thereabouts of such treatment; you might see it in aspects such as an improvement in smoothness at dead slow, ability to start and stop more smoothly, some reduction in noise output, reduction or equalisation of any initial performance difference between forward and reverse, reduced current draw at slowest sustainable speed, increase in maximum speed.

A loco long in storage may develop oxide films on the wiping and rolling contact areas, and a little running will polish this off to restore good current collection. There's also the matter of greases hardening and oil evaporating in storage. Attention to lubrication after more than a couple of years stored is probably a sound plan. If you have made (and kept handy!) notes on how the loco first performed it is possible to assess what degradation occurs in storage, and how effectively original performance is recovered.

cowjam
Posts: 84
Joined: Fri Nov 07, 2014 11:56 am

Re: Running in a motor?

Postby cowjam » Wed Mar 04, 2015 3:12 pm

Thanks for the speedy and in-depth reply!

Any tips on lubrication? I recently bought a can of 'maintenance penetrating spray' from poundland but i've no idea whether i should be using it or not. I haven't yet.

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End2end
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Re: Running in a motor?

Postby End2end » Wed Mar 04, 2015 3:30 pm

I reckon any "SPRAY" will leave far too much lubricant on the model. From what I understand (not that much tbh), you'll need a certain oil added to the model via a "1-drop on a pin" method.
I'll leave it to those that know to advise you (and me) on which oil is to be used.
Thanks
End2end
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bike2steam
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Re: Running in a motor?

Postby bike2steam » Wed Mar 04, 2015 4:44 pm

End2end wrote:I reckon any "SPRAY" will leave far too much lubricant on the model. From what I understand (not that much tbh), you'll need a certain oil added to the model via a "1-drop on a pin" method.
I'll leave it to those that know to advise you (and me) on which oil is to be used.
Thanks
End2end


Along with what bigmet's sez - all sound advice.
http://www.knightwing.co.uk/cgi-bin/com ... Wat&pid=63
for bearings, and smaller moving parts, with C & L Micro-grease for gears.
Last edited by bike2steam on Wed Mar 04, 2015 4:49 pm, edited 1 time in total.

Bigmet
Posts: 7414
Joined: Tue Aug 14, 2007 2:19 pm

Re: Running in a motor?

Postby Bigmet » Wed Mar 04, 2015 4:46 pm

Absolutely right, no spray on lubes on locos.

A thin oil - sewing machine oil, wahl oil or one of the purpose made modelling oils, applied in tiny quantity is what's wanted. If you can see the oil after application, that's too much. Use this on rod pins on steamers, motor shafts if the motor bearing squeals.

Everything else I now use a plastics compatible model grease or graphite powder. Happen to be using Woodland Scenics products for all this because a cheap pack was on offer, Moly grease (dark grey) excellent for wherever its on view like slide bars, PTFE grease on gears and axles, graphite powder for coupler mechanisms and the like. Another good brand that's readily available is Labelle. A pack may seem expensive, but you use so little if you do the job right that it lasts 'forever'.

Beware of any lube that isn't specifically marketed as modelling plastics compatible. It can do a lot of damage which may only become apparent once irreversible: making plastic go runny, or weak and liable to cracking. I once saw was an expensive HO loco that had a Lithium grease used in the axle bearings. Worked beautifully, until the day that the insulating plastics on the driving wheels had been reduced to the strength of something like marzipan, and the wheels literally began falling off the axles. It then turned out that all the other plastic assemblies on the chassis were fast going to the same state. A complete replacement chassis was the cheapest option as there was so much damage.


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