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Date: Thu, 08 Sep 2005 00:19:06 -0500
From: Jim Sower <canarder@frontiernet.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Overvoltage control
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Sort of.  I have the Nuckolls "crowbar" system has the Alt switch 
powering a Master Relay that controls Alternator output.  Turn on the 
Alt switch, the relay closes putting battery voltage to the B+ terminal 
which is jumped to the "F" terminal.  A zener diode in series with the 
power lead to the Alt Relay zenes at 16 or so volts and shorts the Alt 
lead to ground blowing the fuse or CB which causes the Alt Relay to open 
disconnecting the Alternator output from the rest of the electrical system.
No new wire to speak of - just a little stuff in the Alt circuit and of 
course the Alt relay.

Works great for me ... Jim S.

John Downing wrote:

> Does any one know of a simple inline overvoltage control that can be 
> installed in the alternator power lead.  I have an internal regulator, 
> alternator and the overvoltage units at ACS are part of a voltage 
> regulator and quite pricey too.  JohnD