[BC] Harris RF Contactor Maintenance

[Michael Heim, KD0AR]

 I had a contactor that wouldnt switch if the temperature dropped below +10F.  About a week ago, it magically started working.  I'm going to guess that maybe it has something to do with the microswitch alignment.  Trouble is, every time I went out to the doghouse to test, it worked, but its been like this for at least 2 years...i come in, we're still directional, switch it and it would work.  It only happened switching from DA to ND in the morning.

I was thinking that it might have been hardened grease in the bearing, causing the mech to be sluggish, but really, those really shouldnt be greased up.  There really isnt enough movement going on to create a lot of wear.  I'm tempted this spring to pull the contactor and replace the switches and soak the mechanical parts in a good degreaser, just in case my problem returns.

Michael Heim
Chief Engineer, Forever Broadcasting
New Castle PA
WKST WJST WWGY
814-671-0666
ARS KD0AR

From: Chuck Lakaytis <chuck at akpb.org>

I have used the following technique many times in Alaska.  Take two 220
volt lamps in series connected to a line voltage thermostat, close on
temperature decrease.  I have never had one burn out as they are
operating at 1/2 rated voltage.

Gary Peterson wrote:
> I used line voltage thermostats and cone heaters in each ATU cabinet.  The
> cone heaters were purchased at a local hardware store and screw into a
> standard lamp socket.  I never had one burn out in a span of almost twenty
> years.  I will admit that I haven't seen one in a hardware store lately.
> They could probably be ordered.
>
> Gary, KØCX
> CE KFXS, KOUT, KKMK, KRCS, KKLS & KBHB
>
> " Nothing works so well in extreme cold. My facility in Mass. had heat
> lamps on thermostats in each doghouse, pointed at the contactors/ATU's.
> Worked great as long as the bulbs didn't burn out!
> Art "
>
> 

--
Chuck Lakaytis
Director of Engineering, Alaska Public Broadcasting
135 Cordova Street, Anchorage, AK 99501
office  907-277-6300