[TowerTalk] Prop Pitch Grease preference or recommendation

[jimlux]

On 1/8/20 3:04 PM, Steve Bookout wrote:
> Hi Mac,
> 
> I've rebuilt several P/P gear boxes and have had issues in the past with 
> the grease being too thick in the high speed planetary gear area.  When 
> the wx would get really cold (for VA) in the teens, it would want to 
> turn so slowly that it would 'fault' the Green Heron controller.  This 
> was when I had it set up for 'ramping' the speed up/down.  I would just 
> have to change the 'ramp' setting to get it working again.
> 
> So, the last time I did any, I did a bunch of research and found Amsoil 
> Arctic grease. 
> https://www.amsoil.com/shop/by-product/grease/arctic-synthetic-grease/ 
> The performance ratings are fine and comparable to other greases, but 
> it's good for really low temps.  The viscosity reminds me of hair gel; 
> not really thick at all.  And, it synthetic!  Temp range of -75 to 315 
> degrees F.
> 


The other approach is a small thermostatic strip heater. That's what we 
do for dish pedestals that are in areas that get cold, but not arctic. 
(say down to 0F).  Depending on how your controller is set up, you might 
just be able to parallel the heater with the DC power to the motor, so 
you wouldn't need to run additional power. You'd command a move, and the 
motor would turn slowly, but the heater would also turn on, softening 
the grease. After a couple moves it might well have solved the problem.

The Omega catalog is one place to start, but they're also available from 
the usual industrial suppliers like Grainger & McMaster (and, I'm sure 
Amazon from some previously unknown manufacturer in China) - they're not 
an exotic device, and they're available in a variety of resistances, 
power ratings, etc. Finding one to work on 12V or 28V would be no problem.

You could probably also epoxy a resistor the side of the rotator, but I 
think the self adhesive strip heater (or a heater under a band clamp) 
would be more elegant.

{I hesitate to suggest it, but since someone was in my office talking 
about laser propulsion the other day: All you need is a high power (say 
10W) laser on the ground pointed at your rotator on the tower, which you 
have painted or covered with a suitable absorber. You can get a 
frighteningly high power laser for a remarkably low price.  You could 
also use this to melt the ice off your yagi, I suppose. And to solve any 
problems that the plastic owl didn't fix.}