[ARC5] Dynamotor lubrication

[Michael Hanz]

I'll just paste a clip from the article* I wrote for ER a while back and 
updated periodically.  I should also remind you that the more volatile 
components of the grease in new bearings from 1945 have long since 
evaporated, and those components are essential in lubricating a high 
speed bearing.  In other words, just because a dynamotor is NOS or NIB 
does not mean the grease in the bearings is still an effective lubricant.

"As far as lubrication goes, the old greases called out in the TMs were 
never that good for longevity or lubricity. There’s a much better 
product available now - a synthetic based product by Mobil that is 
designed specifically for high speed electric motor bearings, called 
Mobilith® SHC® 100. There might be something better...but I’ve searched 
for a long time - and a couple of colleagues at the National Society of 
Professional Engineers who specialize in lubrication engineering 
enthusiastically confirmed the choice. It comes in a standard grease gun 
cartridge, should be less than $15 or so for a lfetime supply. If you 
can't find it anywhere else, Amazon has it online. Do not use wheel 
bearing grease - it is formulated for higher load, slow speed (~100 rpm) 
bearings, and won't cut it over time at 8,000 rpm. Be aware that this 
grease has a lithium complex thickener that does allow some separation 
of the synthetic base oil over time, especially if you stand a cartridge 
up on end on the shelf to save space. That's perfectly normal, but if 
you want to minimize it simply to keep the mess down (it's a bright red 
color), put it in a plastic sack and pitch it horizontally into the shop 
refrigerator, rather than leaving it up on the shelf in summer heat. In 
the small amounts required in a bearing, the separation is the same as 
any other motor bearing lubricant, and in fact is what allows the grease 
to do its job - the thickener is not a very good lubricant."

*http://aafradio.org/docs/Dynamotors.html

73,
Mike  KC4TOS

On 8/17/2017 7:24 AM, Craig wrote:
>
> I'm getting ready to start going through the dynamotors for my RC-36 
> and SCR-274 installations. What's the current recommendations for 
> lubricants? Most of mine are NOS, but a couple of them are used and 
> I'm betting they need cleaning and lubricating prior to being run
>
> Craig
> Fairchild AT-21
> 42-48053
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>