For what it's worth... here's some mods that I have implemented over the
years to improve the reliability of my HyGain rotor installations. I gave
up on TB3's in favor of (oversized) flanged pillow block bearings with
homemade storm collars for the very reason that Ken & Charlie mention. I
float my rotor shelves to make them continuously self-aligning. I also use
homemade spacers under the rotors to raise the rotor (about 3/8") off the
shelf which greatly reduces the rainwater pooling/splashing up into the
lower rotor bearings. Other mods include replacing the terminal strips on
the rotors with aluminum plates which hold waterproof cable collets. I
transition the internal rotor wiring inside the rotor to a cable whip and
then bring it out to an external J-box (again with waterproof collets) for
making the down lead connections. I also use commercial grade run
capacitors mounted inside the J-box for use with Arduino based rotor
controllers. Each of these mode came about to address past points of
failure, so perhaps someone may find them of use... or prompt some new
ideas. The HyGains tend to stay around because parts are relatively easy to
acquire and they are easy to rebuild, unlike the Yaesu rotors which are
essentially non-serviceable & throw-away.
On another note I have a pair of TICGENs but not installed yet... I don't
have any experience with these so I would appreciate hearing about any
lessons learned if you have used them.
73
Matt
KM5VI
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Charles Gallo
Sent: Saturday, July 14, 2018 12:10 PM
To: Kenneth Goodwin <krgoodwin@comcast.net>
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] T2X brake wedge
The pitting (technically brinelling) of the bearing is typical of ANY ball
or roller bearing with intermittent or stationary use, with even vibration!
(Classic study of auto wheel bearing and rail shipping if you study
vibration failure) You either WAY over design, or use a solid bearing.
Classic in the old days was bronze, but you had lubrication issues.
Today, the answer is...plastic
Filled nylons, filled acetyl, filled Teflon (stop cold flow issues if high
load), or if the budget is there, torlon or vespel. The latter two are so
expensive, once you get past prototype, it pays to have custom molds made,
and cast the smallest part you can to finished shape, but I'm fairly sure a
disk say one inch wide, with a 6-8 id (aka a big washer) 1/8 thick would
hold a large rotating tower with no problems
--
73 de KG2V
Charlie
> On Jul 14, 2018, at 12:53 PM, Kenneth Goodwin <krgoodwin@comcast.net>
wrote:
>
> The T2X brake wedge is a lousy scheme. It allows the antenna to
> move/oscillate a total of 7 degrees in the wind which will pit most
> thrust bearings unless you park it in a different location every so often.
> Pointing accuracy is +/- 7 degrees 3 sigma. My current antenna is
> frozen since the rotator can't overcome the pits in the Rohn TB3
> thrust bearing which means I didn't use the rotator enough. Hurricane
> Ike fractured my brake wedge although it continued to hold the
> antenna. I only keep my T2X because it continues to work after 30
> years which must be taken as a great positive even if I hate the brake
> wedge!! Someday I will have to replace the thrust bearings in the
> tower whereas the design requirement was that only the rotator would
> have to be replaced over the tower's lifetime. Like NASA, the only
> problems I have are the ones I didn't think about. Ken K5RG
>
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