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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