Towertalk
[Top] [All Lists]

[TowerTalk] Fwd: Fwd: X99KP 12VDC RELAY FOR AMERITRON REMOTE ANTENNASWIT

To: towertalk@contesting.com
Subject: [TowerTalk] Fwd: Fwd: X99KP 12VDC RELAY FOR AMERITRON REMOTE ANTENNASWITCHES
From: hanslg@aol.com
Date: Tue, 28 Sep 2010 18:00:45 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Obviously, if any of the contacts weld together, that's it. I know that there 
are problems paralleling diodes but I don't know if, and don't believe, the 
situation is the same for relays. If you don't switch under power, which you 
normally don't do with antenna relays, I believe you, at least almost, double 
the current capacity by doubling the number of connectors. You have to be 
careful how you parallel the connectors, same length,same inductance etc. You 
might even be able to control the current sharing with the "right" lay-out. The 
voltage capacity is not changed though, and I would trust putting several 
contacts in series.

Hans - N2JFS


 

 

-----Original Message-----
From: jimlux <jimlux@earthlink.net>
To: hanslg@aol.com
Cc: towertalk@contesting.com
Sent: Tue, Sep 28, 2010 4:33 pm
Subject: Re: [TowerTalk] Fwd: X99KP 12VDC RELAY FOR AMERITRON REMOTE 
ANTENNASWITCHES


hanslg@aol.com wrote: 
>  LM Ericsson, Sweden (the old telephone manufacturer) had a patent many years 
> ago regarding double contacts in relays. They showed that the reliability of 
> a relay was major increased when you had two relay contacts in parallel. I 
> believe you still find a term for this, just can't remember what. 
> > Hans - N2JFS 
> >  
It kind of depends on what you're trying to achieve. 
Paralleling contacts to improve "reliability" is one thing. 
paralleling contacts to improve current carrying is another 
Paralleling contacts to improve current breaking capability is yet another. 
 
There's a fairly common scheme using 4 SPST relays to implement a "any single 
relay can fail, and you can still make or break the circuit with the remaining 
3" using a "all switch together" scheme. 
 
Likewise, there's a scheme using 2 SPDT relays that will tolerate a single 
failure (think of 3-way light switches at home), but it requires recognizing 
that the failure has occurred. 
 

 
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>