X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-yh0-f53.google.com ([209.85.213.53] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 6984169 for flyrotary@lancaironline.net; Fri, 18 Jul 2014 00:05:12 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.213.53; envelope-from=ceengland7@gmail.com Received: by mail-yh0-f53.google.com with SMTP id c41so1953038yho.40 for ; Thu, 17 Jul 2014 21:04:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type; bh=XrqPXhV8vm/YJE0ZB80Fat0ndOPjUR8qplhCzEw1pSg=; b=03ws0Nr7V4PLOZdXw4G57uCAUgHEifGedUfFQypY818/asaiYCnGSDZAsySwaYHQLB T82OLoLDGsG/fE2Q5S37RLrMVxFdvIMUlNdBxvWtzC3/mQehkXdh8Y09HFT9Vug6DXs4 8Lfr/oaXEWnHbulpaJ5wOWoypGdq4ugBTc1cGoLIT7BU74eDxiYhFTZXBG11hnBQgq82 K+dkeZmxtGcYprOPOOVlmc+Mc8y0szz7bL/V7U64kuTxLEiG34LWN3OocZoGBN46OV6y iquKxPHJ9yI46L64N/6e1KoqGtOV6i6abH0Hx2eGXUIK0v1AWJfeTkhJhy8oZsRltGCj aCVQ== X-Received: by 10.236.113.129 with SMTP id a1mr2914240yhh.127.1405656277352; Thu, 17 Jul 2014 21:04:37 -0700 (PDT) Return-Path: Received: from ?IPv6:2602:306:25fa:d179:1558:3a63:718:ace? ([2602:306:25fa:d179:1558:3a63:718:ace]) by mx.google.com with ESMTPSA id u6sm9106107yhh.5.2014.07.17.21.04.35 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 17 Jul 2014 21:04:36 -0700 (PDT) Message-ID: <53C89D05.2000409@gmail.com> Date: Thu, 17 Jul 2014 23:05:25 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: power circuit design, was: actual current use by a rotary? References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------030709040302050700020105" This is a multi-part message in MIME format. --------------030709040302050700020105 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sorry; multiple Steve s. That question was for Steve B, about the combo switch/breakers. I liked the looks of the fuse block you picked, but couldn't get Bussmann to send me enough info on terminals, etc, so I used their other design, with 1/4" blade terminations. Charlie On 7/17/2014 7:47 PM, steve Izett wrote: > Hi Charlie > "How did I protect the wires going to the circuit breakers?” > I’m not sure I understand your question (sorry if I’m being slow) > > I have a 10 guage feed from battery through key switch to the engine > critical blade fuse buss which is built into the Bussmann fuse block > (see photo). > > I have seperate fuses for Pri and Sec Injectors. From these two fuses > electrons go to separate Pri & Sec 4 pole switches (one pole used to > activate cold start, the other three poles parraleled to meet current > requirements of two injectors, these are mounted with the coil test > switch) [I may remove these switched in the future as my own weighing > of risk is currently on the side of the switches presenting higher > risk and complexity than chances of actual injector failure] > From these switches current flows to the Pri & Sec injector pairs. > Then the individual injectors feed back to the EC2 FETS which then > return to one of my earth busses. > > I used the Bussmann fuse block as it enabled high density power > distribution while enabling me to access each circuit easily for > testing. This fuse block sits at the bottom centre of my panel in > front of a console mounted throttle quadrant making it easily > accessible and central for distribution throughout aircraft. > > Cheers > Steve Izett > On 18 Jul 2014, at 4:24 am, Charlie England > > 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 >> > wrote: >> >> >> >> ------------------------------------------------------------------------ >> *From:* Rotary motors in aircraft > > on behalf of Charlie >> England > > >> *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 >> Well, time for some followup. >> >> My 1st draft for circuit protection looked a lot like what Steve >> describes (thanks, Steve), with individual fuses for virtually >> everything, including an individual fuse for each injector and >> each ignition coil. After ruminating over the actual loads for >> the injectors & coils, I'm having second thoughts. The GM coil >> harness I have in hand has a single DC power wire for all four >> coils that it feeds (obviously isn't a part intended for flight, >> but included in Tracy's installation manual). >> >> The obvious concern is whether an individual coil or injector >> failure has a statistically significant risk of taking out the >> power supply that's fused for the total load. If there's no >> statistically significant danger, weight & complexity could be >> reduced by feeding the coils and injectors as groups. >> >> So, is there any consensus on how to handle injector & coil >> wiring? IIRC, there have been some coil failures in flight; were >> those planes wired with a single fuse/breaker protecting all the >> coils, or with individual fuses/breakers for each coil? What >> about the injectors? >> >> Any failure modes I'm missing? (other than a dead short on a >> supply wire, of course) >> >> Thanks, >> >> Charlie >> >> >> >> >> > --------------030709040302050700020105 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: 8bit
Sorry; multiple Steve s. That question was for Steve B, about the combo switch/breakers.

I liked the looks of the fuse block you picked, but couldn't get Bussmann to send me enough info on terminals, etc, so I used their other design, with 1/4" blade terminations.

Charlie

On 7/17/2014 7:47 PM, steve Izett wrote:
Hi Charlie
"How did I protect the wires going to the circuit breakers?”
I’m not sure I understand your question (sorry if I’m being slow)

I have a 10 guage feed from battery through key switch to the engine critical blade fuse buss which is built into the Bussmann fuse block (see photo).

I have seperate fuses for Pri and Sec Injectors. From these two fuses electrons go to separate Pri & Sec 4 pole switches (one pole used to activate cold start, the other three poles parraleled to meet current requirements of two injectors, these are mounted with the coil test switch) [I may remove these switched in the future as my own weighing of risk is currently on the side of the switches presenting higher risk and complexity than chances of actual injector failure] 
From these switches current flows to the Pri & Sec injector pairs. Then the individual injectors feed back to the EC2 FETS which then return to one of my earth busses.

I used the Bussmann fuse block as it enabled high density power distribution while enabling me to access each circuit easily for testing. This fuse block sits at the bottom centre of my panel in front of a console mounted throttle quadrant making it easily accessible and central for distribution throughout aircraft. 

Cheers
Steve Izett
On 18 Jul 2014, at 4:24 am, 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
 
 
 
Well, time for some followup.

My 1st draft for circuit protection looked a lot like what Steve describes (thanks, Steve), with individual fuses for virtually everything, including an individual fuse for each injector and each ignition coil. After ruminating over the actual loads for the injectors & coils, I'm having second thoughts. The GM coil harness I have in hand has a single DC power wire for all four coils that it feeds (obviously isn't a part intended for flight, but included in Tracy's installation manual).

The obvious concern is whether an individual coil or injector failure has a statistically significant risk of taking out the power supply that's fused for the total load. If there's no statistically significant danger, weight & complexity could be reduced by feeding the coils and injectors as groups.

So, is there any consensus on how to handle injector & coil wiring? IIRC, there have been some coil failures in flight; were those planes wired with a single fuse/breaker protecting all the coils, or with individual fuses/breakers for each coil? What about the injectors?

Any failure modes I'm missing? (other than a dead short on a supply wire, of course)

Thanks,

Charlie







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