[TowerTalk] Rotator Question

[Grant Saviers]

The TVI  was most likely an arc or spark when the voltage exceeded the 
breakdown voltage of the oil film in the bearing.  race - oil -ball -oil 
- race. So the rotator halves are insulated from each other by the oil film.

Electrical Discharge Machining (EDM) machines by spark eroding metal.  
That is what is happening to your rotator races and bearing balls.  The 
oil/grease also degrades from the arc burning through the oil film.

It doesn't take much of a wire to drain static charge or short out RF 
potential around a bearing.  My choice would be 12 to 16ga stranded for 
ease of finding large ring terminals, mechanical durability, 
flexibility, and dressing it for rotation.

Of course a 12ga wire will be worthless if it is the primary conduction 
path for a direct lightning hit.

Grant KZ1W

On 5/22/2011 11:44 PM, pfizenmayer wrote:
>
>> FWIW, I had to put a wire across my rotor because RF currents
>> going though the bearings caused TVI.
>> Rick N6RK
> On 5/22/2011 11:41 AM, Robert Chudek - K0RC wrote:
>> Please tell me what this #2-#4 wire is going to do that the Faraday
>> shield effect of the tower legs around the rotor is not going to do? Or
>> the metal of the rotor bell-housing itself? That pot is buried several
>> layers deep, covered with metal. Does a #2-#4 wire have some priority
>> for lightning? I really need to know, as I have been extremely lucky to
>> escape any rotor damage, even with several lightning direct hits to my
>> tower.
>>
>> 73 de Bob - KØRC in MN
> and on 160 I got all kinds of BC IMOD  until I tied across top and bottom .
>
> Hank K7HP
>
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