[TowerTalk] Lightning damage to rotor housings (Was: Which thrusebearing?)

[Gary Schafer]

Well, after all that "authoritive" reporting I don't think anyone should
ever worry about lightning damaging anything on a tower again. Why spend the
time to bypass or ground anything. If no authoritive figure ever sees the
damage then it must not exist in the first place. Even though the laws of
physics tell you differently.

73
Gary  K4FMX

> -----Original Message-----
> From: towertalk-bounces at contesting.com [mailto:towertalk-
> bounces at contesting.com] On Behalf Of Robert Chudek - KØRC
> Sent: Thursday, December 14, 2006 4:20 AM
> To: towertalk at contesting.com
> Subject: [TowerTalk] Lightning damage to rotor housings (Was: Which
> thrusebearing?)
> 
> Okay... you guys theorized ever which way to Sunday about damage to rotors
> from a lightning strike. Most everyone on the list has had a rotor or two
> or
> three during their radio career. I'll be blunt, I didn't like your
> suggestions and all the jerry-rigging ideas that were being tossed about.
> So
> I went to the experts. The two companies that have been in the business of
> rotor sales and service. That would be C.A.T.S. and Norm's. Here's my
> information request and the replies I received from them both:
> 
> KØRC>>>Hello Dr. Rotor (Craig) ! There is a discussion warming up on the
> TowerTalk reflector regarding lightning damage to rotor housings when an
> antenna mast is struck and discharged down through the tower to ground.
> What
> kind of damage have you seen to rotor housings, bearings, balls, and races
> over the years? I am curious about physical damage more than electronics
> being destroyed. Does the bearings and races provide an adequate, low
> resistance path for a high current discharge like this? Thanks in advance
> for any insight and real-world experiences you can provide. 73 de Bob -
> KØRC
> in MN
> 
> CRAIG>>>Hi Bob :
> Sounds like most of the discussion is pure conjecture and no one has yet
> chimed in from experience.
> OK, from 30 years of experience working with rotators :  A metal housing
> protects the interior parts, as does the framework of the tower structure
> surrounding a rotator. Lightning damage to a rotator has been almost
> unheard
> of; with the few cases we have seen suspected of coming from the surge on
> the cable itself. In my early days when I was in the TV antenna business,
> I
> saw numerous cases of the rotator wiring arcing over to the legs of the
> metal tower and the rotator itself surviving just fine.
> Now, I would suspect that a rotator with a streamlined design from top to
> bottom would be the least susceptible to a lightning surge; but I haven't
> seen enough data to back this theory up.
> Oh, and to answer your other question. Never ever have we seen any damage
> to
> bearings or races.
> Craig,
> C.A.T.S.
> 
> 
> KØRC>>>Hello Norm...
> 
> There is a discussion warming up on the TowerTalk reflector regarding
> lightning damage to rotor housings when an antenna mast is struck and
> discharged down through the tower to ground.
> 
> NORM>>>What kind of damage have you seen to rotor housings  [none],
> bearings
> [none], balls [none], and races [none  on any of these that I can
> attribute
> to lightning] over the years? I am curious about physical damage  [I don't
> see much physical damage, I did have one with a broken off upper mast
> support but that was because the whole tower came down in the lightning
> storm]  more than electronics being destroyed.  [Everything I get in has
> burned up electronics mostly in the control units with lightning coming
> down
> the rotor cable.]  Does the bearings and races provide an adequate, low
> resistance path for a high current discharge like this? [maybe if they
> suffer severe physical damage, guys just chunk them and I never see them,
> I
> don't know. This is all based on what I recollect from the dozen or two
> over
> the last few years.]
> 
> Thanks in advance for any insight and real-world experiences you can
> provide.
> 
> 73 de Bob - KØRC in MN
> 
> 
> So there you have it. Create a rube goldberg solution to a non-problem if
> you like. I'm not going to waste any time, energy, or money protecting my
> rotor housing from lightning. Oh, and I can speak from experience, my
> tower
> has been hit by lightning numerous times and I have never had any damage
> to
> the rotor on the tower.
> 73 de Bob - K0RC
> 
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk