Today's Message Index:
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1. 05:56 AM - Re: Re: IBBS battery with B and C alternators? (Robert L. Nuckolls, III)
2. 10:33 AM - Re: IBBS battery with B and C alternators? (Jeff Page)
3. 11:05 AM - EFII ignition and injection Z-13/8 (johnbright)
4. 12:53 PM - 2016 List of Contributors (Matt Dralle)
Message 1
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| Subject: | Re: IBBS battery with B and C alternators? |
At 05:24 PM 12/23/2016, you wrote:
>
>The only contactor failure I've had is when it welded itself shut,
>due to a short in the starter motor. It's quite unusual not being
>able to turn off the aircraft..
>
>On 23Dec2016, at 7:12 PM, user9253 <fransew@gmail.com> wrote:
>
>
>
> > If you're going to that much trouble why not just have two
> independently switched contactors?
>
>There is not much trouble, same number of components either
>way. The relay has the advantage of less current, less weight, less
>cost, and less space. I am not necessarily recommending this
>circuit. Just offering it for others who want redundancy.
Contactor failure (or failure of the
control wiring/swtich to a contactor
is rare. Figure Z-13/8 was designed
so that ENDURANCE mode flight was not
only possible with the contactor
deliberately opened to reduce en
route energy demands.
Have you done a load analysis of your
proposed installation? Have you selected
a system architecture? I'm betting
that with a little pre-planning and
adjustment of architecture, a Plan-B
can be identified for every single-
failure event but without adding a lot
of weight, cost-of-ownership and system
complexity.
Electrical system failures as root or
even contributing cause for a bad day
in the cockpit are exceedingly rare.
Most bad days in the cockpit arise
from poor pilot preparedness for steering
around the many inevitable pot-holes
in their flying experience.
I'll suggest a review of the Z-figures,
accompanying notes and supporting narratives
in the 'Connection would be useful.
Particularly the chapter on system reliability
(where 'system' includes prop-to-tailcone
environs and all components in between).
If you don't have a paper copy of the
'Connection, you can download a .pdf at
http://www.aeroelectric.com/Book/AEC_R12A.pdf
I've been out of pocket for the last few
days . . .had a melt-down of my office
computer. Just got a re-build up and running
late yesterday. Leaving for Wichita today
for Christmas celebrations. Be back on
line late Sunday. In the mean time, let's
see if we can figure out why Z-13/8 WILL NOT
serve to PLAN for any real risks to the
enjoyment of your airplane.
Lets do failure mode effects analysis to
your proposed system with a goal of keeping
ANY and ALL single failures from creating
an EMERGENCY . . . the goal is to upgrade
a component because you're tired of replacing
it . . . not because it damned near got you
killed. FMEA is the easy, light, most economical
way to craft an electrical system and mitigate
any worries associated with flying it.
Merry Christmas folks! See you in a few
days.
Bob . . .
Message 2
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| Subject: | Re: IBBS battery with B and C alternators? |
In the event of an emergency landing or fire, it is necessary to turn
off both switches.
I suggest making that ergonomically easy to do in a single motion.
Jeff Page
Dream Aircraft Tundra #10
> Time: 08:14:43 AM PST US
> Subject: AeroElectric-List: Re: IBBS battery with B and C alternators?
> From: "user9253" <fransew@gmail.com>
>
> Here is a circuit for those concerned about the master contactor
> failing. An automotive
> relay is connected in parallel with the master contactor. The relay
> is disabled during engine starting to prevent excessive current from flowing
> through the relay contacts. Prior to turning on the master
> contactor, the relay
> can be energized to be sure that it works. The relay must be shut off to
> start the engine. After engine start, the relay may be turned back
> on. If the
> alternator fails, the battery master contactor can be shut off to
> conserve energy.
> During cruise flight, the relay will only carry battery charging
> current. Aircraft
> load current will flow directly from the alternator to the main power bus,
> not through the relay.
> When playing with avionics in the hangar with the engine off, the
> relay can be
> turned on instead of master contactor. Notice that the arrows on
> arc-suppression
> diodes point towards positive.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=464274#464274
>
>
> Attachments:
>
> http://forums.matronics.com//files/contactor_bypass_462.pdf
> http://forums.matronics.com//files/contactor_bypass_143.jpg
Message 3
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| Subject: | EFII ignition and injection Z-13/8 |
With EFII ignition and injection is Z-13/8 a good choice?
I'm not sure the current draw of one pump, one ignition, and injectors; could be
too much for the 8 amp alternator.
Is Z-13/8 suitable for a 20 amp backup alternator or would that lead one to Z-12?
I know I need to do a load analysis.
Thanks for the LA-IFP accident report.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=464299#464299
Message 4
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| Subject: | 2016 List of Contributors |
Dear Listers,
The 2016 Matronics Email List and Forum Fund Raiser officially ended a couple of
weeks ago and it's time that I published this year's List of Contributors.
It is the people on this list that directly make these Email Lists and Forums
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Contributions keep the servers and Internet connection up and running!
You can still show your support this year and pick up a great gift at the same
time. The Contribution Web Site is fast, easy, and secure:
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Or, by dropping a personal check in the mail to:
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581 Jeannie Way
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I also want to thank Andy, Bob, George, and Jon for their generous support through
the supply of many great gifts this year!! These guys have some excellent
products and I encourage you to visit their respective web sites:
Andy Gold - The Builder's Bookstore - http://www.buildersbooks.com
Bob Nucklolls - AeroElectric - http://www.aeroelectric.com
George Race - Race Consulting - http://www.mrrace.com
Jon Croke - HomebuiltHELP - http://www.homebuilthelp.com
And finally, I'm proud to present The 2016 Fund Raiser List of Contributors:
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