Mailing List flyrotary@lancaironline.net Message #61149
From: Steven W. Boese <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: power circuit design, was: actual current use by a rotary?
Date: Fri, 18 Jul 2014 05:28:12 +0000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Charlie,

The switch-breakers are on a bus bar with other breakers.  The bus bar also feeds a block of fuses.  The feed to the bus bar is a #8 wire connected to a battery contractor without a fuse.

Steve Boese

On Jul 17, 2014, at 2:26 PM, "Charlie England" <flyrotary@lancaironline.net> wrote:

Thanks, Steve.

Guess I should have known even more options would turn up. :-)

I like the idea, but how did you protect the wires going *to* the switch-breakers? Are they just on a high current bus with the rest of your breakers? If so, it might not work for me, since I'm using automotive fuse panels. Right now, I've planned for multi-pole injector switches wired as shown in the manual (but with a separate pole for each injector), mounted next to Tracy's engine control panel (the coil test switch is there, too).

Charlie


On Thu, Jul 17, 2014 at 2:08 PM, Steven W. Boese <flyrotary@lancaironline.net> wrote:


From: Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of Charlie England <flyrotary@lancaironline.net>
Sent: Thursday, July 17, 2014 12:14 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] power circuit design, was: actual current use by a rotary?
 Charlie,
 
I chose to install switch type circuit breakers, one for the primary injectors and one for the secondary injectors.  I did this because if one injector fails, the backup function requires the corresponding injector of the other rotor to be shut off and then the cold function to be activated.  If there were a power draw that tripped the breaker, the result would already take care of that first step.  The down side is that the cold switch needs to be used for the backup function instead of being taken care of by the second pole of the recommended DPDT injector switch.  This required no additional space on the panel.
 
I did the same thing for the leading and trailing coils but for testing purposes rather than risk mitigation.

Steve Boese
RV6A, 1986 13B NA, RD1A, EC2

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