[Boatanchors] Switch help please.

[WA5CAB at cs.com]

Curt,

I agree with Ian.  With switches as opposed to connectors, it isn't unusual 
for the DC voltage rating to be considerably lower than the AC one at the 
same current  It has to do with breaking the arc on opening.  With AC, the 
voltage across the opening contacts and therefore the current and voltage 
sustaining the arc will pass through zero repeatedly after the switch opens.  
With DC it won't immediately.  So it isn't uncommon to see switches rated at 
say 3 amps 125 VAC or 32 VDC.  Or something similar to that.  Although the 
guy at Carling may have been correct in saying that the number isn't in their 
current catalog, he's undoubtedly wrong about the voltage rating.

In a message dated 1/19/2011 2:07:51 PM Central Standard Time, 
ianwebb5 at comcast.net writes: 
> The picture of it shows that it's 250 VAC
> 
> Should be OK for what you're doing.
> 
> <
> http://www.tubesandmore.com/scri
> pts/foxweb.dll/moreinfo at d:/dfs/elevclients/c
> emirror/ELEVATOR.FXP?item=P-H527>
> 
> Google is your best friend...!!!   Sort of anyway!   
> 
> Ian, K6SDE
> 
> >-----Original Message-----
> >From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-
> >bounces at mailman.qth.net] On Behalf Of Curt
> >Sent: Wednesday, January 19, 2011 10:22 AM
> >To: boatanchors at mailman.qth.net
> >Subject: [Boatanchors] Switch help please.
> >
> >I am needing to replace the DPDT AM/Phone toggle switch ( SW-2) for a 
> Globe
> Scout.  The
> >existing switch is not original equipment, was bypassed, and is broken.
> The circuit shows this
> >switch switches ~ 350VDC to the modulator tubes.
> >
> >The meter switch is labeled 3A at 250 VAC, and is the same WRL part 
> number
> (WRL 2101-
> >001) as the AM/Phone switch.   I found a Carling DPDT switch at AES 
> labeled
> P-H527, but
> >when I called the Carling factory they said that wasn't one of their
> numbers and that none of
> >their switches were rate for more than 24VDC.  In fact he laughed when I
> asked the
> >question.  AES couldn't tell me the insulation strength of the switch 
> they
> sell.
> >
> >I'm thinking that the Carling person I talked with was thinking about 
> high
> current capability,
> >maybe unfamiliar with the application.  Appreciate advice about 
> appropriate
> switch for this
> >application.  Surely these are routinely needed for boatanchors.
> >
> >73, Curt KB5JO
> 
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480