[TowerTalk] X99KP 12VDC RELAY FOR AMERITRON REMOTE

[Jim Lux]

On Sep 27, 2010, at 9:10 PM, "Jim Thomson" <jim.thom at telus.net> wrote:

> Date: Mon, 27 Sep 2010 20:50:48 -0700
> From: Jim Lux <jimlux at earthlink.net>
> Subject: Re: [TowerTalk] X99KP 12VDC RELAY FOR AMERITRON REMOTE
> ANTENNA SWITCHES
> 
> 
> And just how do you think they do a "double make" contact? :)
> 
> Bridge the two armature contacts on a dpdt or dpst relay and you get a double make spdt or spst.
> 
> ##  whoa.  P+B makes SPST-DM  relays.  They are configured just like any contactor.  It's 2
> sets of contacts IN SERIES.  The COM [ moveable part] is shaped like a 'T'... and comes crashing
> down on the TWO 'throws.   One throw is the input, the 2nd  throw is the output.  Contactor's
> are built the same way, except times  two or three.    The concept is when shutting off stuff like
> motor's, etc, the back emf is split into TWO gaps, = zero arcing. 
> 
> ##  IF you take a DPDT  or DPST  relay, and parallel all the contacts, you just get a 
> higher current rated  SPDT  or SPDT.   I dunno if you would call it DM.   
Not exactly. In the bridge the armature scheme, the contacts are in series, just like the pb relays you describe.  Granted the usual t shaped armature thing as contractor isn't really rf suitable, at least at 30MHz


> I would call it
> redundant contacts.   It's an excelllent config, when using mech realys for remote switch's.
> If you double the current rating, you quadruple the power rating. The way the poer can go open is
> if both contacts go open. 
> 
> ## The only other config that is reliable is  vac relays. 
> 
> Jim  VE7RF  
> 
> 
> 
> 
> On Sep 27, 2010, at 8:39 PM, "Ron W8RJL" <youngron at verizon.net> wrote:
> 
>> For anyone who might be confused by the armature and parasitic verbage here 
>> is what Allan Bradley has to say about Form X relays:
>> 
>> 
>> A Form X contact arrangement is one which has single-pole, single-throw, 
>> normally open double-make contacts. The function of this arrangement is to 
>> close a circuit when actuated.
>> 
>> Forget about parasitics and armatures. It is just a contact configuration.
>> 
>> 73,
>> Ron W8RJL
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