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

[Gene Fuller]

Not quite on the voltage, I think.  Whether open or closed wouldn't the 
first in the series have full voltage to ground or to the coil ?  Onl;y if 
they were indeed mechanically and electrically daisy chained (difficult to 
do) would the voltage divide up through the series.
Gene / W2LU

----- Original Message ----- 
From: <hanslg at aol.com>
To: <towertalk at contesting.com>
Sent: Tuesday, September 28, 2010 6:00 PM
Subject: [TowerTalk] Fwd: Fwd: X99KP 12VDC RELAY FOR AMERITRON REMOTE 
ANTENNASWITCHES


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