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From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [FlyRotary] FW: [FlyRotary] Re: Cooling fans
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
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Date: Mon, 11 Aug 2003 18:50:02 -0400
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"Tommy James" <twjames@healed.org> wrote:


>>>I think you both said the same thing in different ways. Right? <<<

Yes, except fans are pretty high current inductive devices, and will likely 
burn out the contacts on most switches in pretty short order.  It's probably 
easier to size a relay than a switch to that amount of current draw, although 
I suspect Lynn knows something I don't <g>. Additionally, the relay can be 
spec'ed to break-before-make (that's the way typical relays work), whereas as 
a switches contacts get tired they can actually have NO, COM and NC contacts 
connected together all at the same time during the switching cycle... with the 
shunt applied across one side of the DPDT switch that's a recipe for a dead 
short and a blown breaker.  Been there, done that.

      <marv>