[TowerTalk] Lightning Protection of rotors/remote switches etc

[jimlux]

john at kk9a.com wrote:
> I too have replaced many many potentiometers, hash filters and a few motors 
> on TIC ring rotators after lightning strikes.  Is there a way to protect 
> them?  Do MOVs protect the motors?
> 
> John KK9A
> 
>
You might want to look at using vacuum spark gaps and series LC filters. 
    Or even neon bulbs as OVP.

MOVs are lossy clamps, so when the voltage exceeds their threshold they 
start to conduct, but the voltage stays high.  A spark gap (or NE-2) 
fires, and then the voltage drops quite low.  Followed by a low pass 
filter (RC or LC), the short spike gets flattened out, and in any event, 
doesn't have much energy.

You also need some current limiting on the line, if the line resistance 
doesn't provide it.