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1. 08:26 AM - Re: Wiring for Aircraft With Dual Electronic Ignition (Justin Jones)
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Subject: | Re: Wiring for Aircraft With Dual Electronic Ignition |
Thank you all for your help and feedback! I will get on the forum and
look at the diagrams and figure out something that will work for me.
Thanks again!
Justin
On Feb 25, 2014, at 6:34 PM, Bob McCallum
<robert.mccallum2@sympatico.ca> wrote:
> Justin;
>
> The 10A fuse on the starter relay serves no purpose.
> Closing the switch leading from the =93emergency=94 buss to the Blue
Mountain EFIS back feeds the whole avionics buss through the 5amp fuse.
It will most certainly fail. (and if the avionics master is closed also
back feeds the main buss) What you=92re trying to do requires a second
diode coming from the avionics buss, not just the single diode you=92ve
shown.
> The four circuits on the left of the =93emergency=94 buss back feed
the main buss, making it impossible to isolate and also most likely the
fuses will fail as they are likely not large enough in combination to
support the whole of the electrical load. Guaranteed to fail if you
touch the =93starter=94 switch with the master off. Each of these four
circuits, similar to above, require two diodes each to achieve what
you=92ve attempted to accomplish.
> The =93master=94 switch should be switching the ground side of the
master relay, not the =93live=94.
> I don=92t see any active =93low voltage=94 warning, unless that is the
function of the circuit you=92ve labeled =93alt fault=94?? Does your
regulator support low voltage notification?? Many =93alternator failure=94
lights do not achieve this goal.
> Does your ELT actually require aircraft power?? This is rather
unusual.
> Nothing should be an =93emergency=94. The word should not be part of
an electrical system. In Bob=92s terms when the alternator fails, you
revert to the pre-thought-out =93plan B=94 which may entail switching
off the main buss and relying on the =93Endurance=94 buss for minimal
electrical loads to get you to your destination. It shouldn=92t
constitute an =93emergency=94.
> =93Pulling fuses=94 should not be part of your =93plan B=92 scenario,
but I see a note whereby you =93pull in case of buss failure=94.
Switches are more convenient. In a =93properly designed=94 electrical
system there is no need to have any fuses accessible in flight. Nothing
individually should be =93critical=94 and troubleshooting should be done
after the flight is over, not in the air.
> Suggest reading AeroElectric connection and studying some of the =93Z=94
drawings as most of what you are trying to achieve is elegantly covered
and will allow you to fly, in the case of most failures, until you
exhaust your fuel supply. (assuming proper battery maintenance)
> By all means re-invent the wheel if you wish, that=92s what
=93experimental=94 is all about, but understand what=92s been developed
before and the reasons behind why it=92s been done the way it was, and
then tweak to suit your unique requirements.
> As for your question on solid state relays, be aware that they are
very reliable as long as they are properly heatsinked and kept within
their ratings. We use them at work and get fantastic reliability as long
as we over rate them. When operating at their design limits there are
some failures, both fail open and fail closed. We=92ve found that if we
load them in the 30% to 50% range they are close to perfect. (no
failures) Their chief advantage is very limited power consumption to
operate the relay itself, conserving an extra amp or two of load to add
to your battery endurance. Heat is their enemy and that=92s the reason
behind de-rating to ensure they stay cool. We always keep them under 50%
current rating.
> Keep asking, we=92ll help you sort it out to be head and shoulders
better than spam cans and achieve the reliability you require.
>
> Bob McC
>
> From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Justin Jones
> Sent: Monday, February 24, 2014 10:39 AM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: Wiring for Aircraft With Dual Electronic
Ignition
>
> I am fairly unexperienced and new at the experimental building hobby.
I am building a Bushcaddy L164 and I am putting dual electronic ignition
on it. I absolutely need this to work at all times since I am flying
over non-forgiving terrain in Alaska. The new systems are very reliable
and I am confident that with a redundant system (EIGN-4-2R through the
company fly EFII ) I will be fine as long as I can supply power to the
system. I have drawn up a schematic on how I plan to wire the system
and wanted some input from some experts out there to see if I have done
anything incorrectly. I have attached the diagram. I have also
considered using solid state relays in the system. I would use them for
all of the relays except the starter relay. Any thoughts on this? I
have found solid state relays that are rated for all of my applications
to include the Battery Master (rated at 300A continuous and 500A for 1
sec).
>
> Thank you for your time and consideration.
>
> Justin
>
> <image002.jpg>
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