[AMRadio] Dow Key


Mike Sawyer w3slk at uplink.net
Sat Sep 16 20:27:40 EDT 2006


Although that is a good place to look, I think 15 seconds is pretty long for 
residual magnetism to hang on. What I have found and maybe the case with 
your relay is the 'lid' that keeps the solenoid in place is easily bent. 
There may be a deformation or something there abouts that would prevent it 
from retracting all the way out. Also, be careful soldering on to the 
terminals, they are very delicate and do not withstand a whole lot of heat 
applied to them.
Mod-U-Lator,
Mike(y)
W3SLK
----- Original Message ----- 
From: "K4XM, Mike Dorworth" <k4xm at arczip.com>
To: "Discussion of AM Radio in the Amateur Service" 
<amradio at mailman.qth.net>
Sent: Saturday, September 16, 2006 6:59 PM
Subject: Re: [AMRadio] Dow Key


> Okay... maybe I missed something the day they taught magnetism.  I have
> a Dow Key that sometimes stays energized with the source completely
> removed.  Not every time but sometimes.  It has a 115 vac coil and
> nothing else.  No capacitor across it, no nothing.  It's as if the coil
> is acting as a capacitor and retaining enough of the 115 vac to keep the
> armature of the relay engaged.


It's name is " residual magnetism" High quality relays have a tiny brass
screw in the center of the armature with an adjusting nut so that the
armature can never quite touch or get too close to the pole piece. You might
try a piece of scotch tape over the pole piece to keep it from getting too
close.. Mike

----- Original Message ----- 
From: "Rick Brashear" <rickbras at airmail.net>
To: <AMRadio at mailman.qth.net>
Sent: Saturday, September 16, 2006 5:57 PM
Subject: [AMRadio] Dow Key


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