inverter overload (was transformer inrush) [RE-wrenches]

[sunwise]

Windy wrote:

As long as you use all four terminals on the pressure switch, the 
contacts are all in series -- whether it switches both sides of the 
power (2 hots), or one side, with a series-link between both the sets 
of contacts.

Hey Windy,

Not sure I am following you here, maybe you are stating it from a code
perspective.  It may not meet code, but I believe I am paralleling the
two sets of contacts and I use two jumpers.  Aren't the contacts on this
switch just like a 2pst relay, or for that matter any 2pst switch.  Some
(Allan) might argue that they don't make and break at exactly the same
moment, and that could be more to the issue.  I'll consider a relay deal
in the future, but at this moment I'm not feeling a need to replace a
bunch of pressure switches.

Kurt Nelson  

-----Original Message-----
From: Windy Dankoff, Dankoff Solar [mailto:windy at dankoffsolar.com] 
Sent: Thursday, January 08, 2004 2:04 PM
To: RE-wrenches at topica.com
Subject: Re: inverter overload (was transformer inrush) [RE-wrenches]

Allan,

As long as you use all four terminals on the pressure switch, the 
contacts are all in series -- whether it switches both sides of the 
power (2 hots), or one side, with a series-link between both the sets 
of contacts. (The latter is done to avoid breaking a grounded 
conductor). Whether they are on opposing sides or adjacent to each 
other in a circuit makes no difference.

So, all contacts in series is already the assumption on which the 
contact ratings are based. You can't compensate for undersized 
contacts by series or parallel connection.

Windy


Allan Sindelar wrote:
>
>I'm pulling out one piece from Windy's reply to make a noncorrective
>inquiry.
>>
>>  It won't help much to parallel the two sides of the p. switch
because
>>  the 2 sets of contacts don't make or break exactly simultaneously.
>>  One set of contacts will take the full current during the make or
>>  break. The only way to prevent contacts from welding or burning is
to
>>  use a "heavy duty" p. switch (or a relay) rated for 2X the current
of
>>  the pump.
>>
>>  Windy
>
>Windy, I think it was you who advised wiring the two sets of pressure
switch
>contacts in series with DC to reduce arcing. It seems to me that this
would
>be just as effective with 120V AC as with DC, even granted that AC is
far
>less prone to arcing.
>
>Allan

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