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Re: [TowerTalk] Prop pitch magnetic reed switch

To: "Mel Whitten" <mel@melwhitten.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] Prop pitch magnetic reed switch
From: "Floyd Sense" <fsense@copper.net>
Date: Fri, 15 Jul 2005 12:13:24 -0400
List-post: <mailto:towertalk@contesting.com>
Having worked on reed-relay based devices for a while years back, I can tell 
you that this is the typical failure mode for reed switches, whether used 
beyond their ratings or not.  Once a reed has "tacked", it will be more 
prone to stick again in the future.  Replacement is the proper action.

73, K8AC

----- Original Message ----- 
From: "Mel Whitten" <mel@melwhitten.com>
To: <towertalk@contesting.com>
Sent: Thursday, July 14, 2005 10:40 PM
Subject: [TowerTalk] Prop pitch magnetic reed switch


>I am using a larger prop pitch rotator with a M2 RC2800P-A controller and 
>Mike's reed switch conversion kit for sending the digital pulses.  For 
>several days, the rotor was operating intermittently.. motor would run a 
>couple seconds and then stop. After a few attempts to get it to run 
>normally, it would start working again and all was well.  I found when the 
>rotor was working OK, the 11v DC digital pulse was about 5ms in duration 
>and repeated every 25ms in Mode 0 and Speed 5. When it was not working, the 
>pulses were not present.  A continuous short across the pulse leads (less 
>than 2 ohms) was observed.  At the rotator, I pulled the cover off the 
>motor and confirmed the magnetic reed switch was "stuck" closed.  A light 
>"tap" on the switch however, opened the contacts. I ran the magnet across 
>the switch again while observing the Simpson 260 and contacts closed but 
>remained closed after moving away from the magnet.  Again, another tap and 
>the circuit opened back up.  It appears
>  the contacts are sticking... or it is possible the switch itself has 
> become magnetized?  Maybe just enough to hold them closed until subjected 
> to a slight vibration?  If so, is it possible to degauss the switch?  The 
> switch mfg appears to be G R I, p/n P-20-A with mfg date of 1-Q-97.  I was 
> not successful in finding this switch on in my search on the net. M2 
> responding quickly and is sending a new switch.  I am sure this will fix 
> my problem, but just curious about the failure.  I've been using this prop 
> pitch for about 2 1/2 years, but I believe original owner did not have it 
> in service very long. Has any one had a similar experience with their prop 
> pitch? Any comments would be appreciated.
>
> Mel, K0PFX
> St Louis
>
> _______________________________________________
>
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
> any questions and ask for Sherman, W2FLA.
>
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> 


_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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