[Boatanchors] Relay Repair - Demagnetization Question

[Mark Foltarz]

I experienced the phenomenon with a Scott 800 radio.  The mute relay kept sticking and by all appearances it was the coil and core 
staying magnetized. Indeed the relay uses DC.

After a lot of head scratching I placed a piece of scotch tape across the coil assembly to prevent it from making contact with the contactor arm (terminology ? )

Has not stuck since.

de KA4JVY

Mark



----- Original Message ----
> From: Glen Zook <gzook at yahoo.com>
> To: boatanchors at mailman.qth.net; Ron <ronami at yahoo.com>
> Sent: Tue, February 2, 2010 11:31:22 AM
> Subject: Re: [Boatanchors] Relay Repair - Demagnetization Question
> 
> In theory, yes.  But, unfortunately, in reality, no!  There are all sorts of 
> relays "out there" that, when run from DC, definitely get magnetized.  The "fix" 
> is to reverse the connections periodically.  Now when run from AC the problem 
> doesn't exist.
> 
> Glen, K9STH
> 
> Website:  http://k9sth.com
> 
> 
> --- On Tue, 2/2/10, Ron wrote:
> 
> Relays are designed with very low coercivity (or remnance) cores. There is no 
> need to ever demagnetize a relay.
> 
> 
>       
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