[TowerTalk] Add on 3" mast brake?

[Leeson]

I do two things here on windy ridge: when the power's off I use relays 
to put a short circuit across the DC motor in the prop pitches and also 
the TIC Ring (2-motor). A DC motor with shorted terminals acts as a 
brake all by itself.

Also, I use the bigger BMW rubber coupling ("flexdisc" or "guibo") from 
the 750il and 850ci, PN 26-22-1-229-065. Kurt made me a lovely adapter 
plate setup for the prop pitch from my drawings.

A while ago, I did an rough analysis of the rotating forces from wind 
shear and vortices, and am convinced that even a completely symmetrical 
antenna will suffer from the resulting buffeting.

To keep the shaft and gear together in various rotators, I use green 
600-series Loctite bearing retainer between the gear and the shaft (609 
or 638 for really tough situations). That keeps the key from giving way 
on the shaft and causing play.

Dave

On 11/14/22 7:07 PM, john at kk9a.com wrote:
> Yes the larger prop pitch motors have a lower gear ratio but the gear box is
> larger and considerably heavier so I assume it is stronger.  I am not sure
> if the medium has any more turning torque than the small or how resistance
> to back turning compares. Most rotators made for ham radio do not hold up
> well for medium to large antennas so you have a tough problem.
> 
> I wonder who (if anyone) is working on prop pitch motors these days?
> 
> John KK9A
> 
> 
> 
> 
> Grant Saviers KZ1W wrote:
> 
> <snip> The small PP I had from K7NV showed a surprising amount of backlash,
> more than Kurt thought it should have.  He also commented that the small
> unit has the highest total gear reduction and thus the most resistance to
> turning.  I have a medium PP that needs rebuilt, but am not sure I want to
> get into it and where would I get parts?
> 
> Grant KZ1W
> 
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