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Bill the Schottky diodes are from RS (Radio Spares) I just searched through the specs untill I found the ones with the lowest voltage drop and highest current rating, with size also being a factor. Most are 42CTQ030 from IR with a 40A rating you could probably try Digikey.
S4 & S6 are 4PDT switches, they are harder to find and of course more expensive. They are NKK S42 and do take up a bit of room. Originally I had it set up so I could select a battery but I realised that the extra complexity wasn't worth it and this way I'm assured that the better battery is supplying the engine.
Greg
Wow, what a problem! I switched from the daily digest to the individual
msgs prior to asking questions so that I would get faster answers....I
only received two msgs since I switched...This being one of them. I
then went to the archives and found that there had been several replies
which I did not get.. I guess I should go back to the daily digest!
The schottky diodes...I assume that you used them to reduce the amount
that the diode pulled your voltage down? Where did you find a supplier
for them? I understand that they are fairly expensive??
What kind of switch is SW6 and SW14? 12 pole??? Quadruple throw???
Looks like your setup would work fine. The only real difference from
what I was thinking is that I was trying to be able to select the
voltage source while you are just providing a dual source with no
selection. Yours is probably better since my switch would provide a
possible failure point which would kill both sources....
Bill B
----- Original Message ----- From: "Greg" <greg@itmack.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, October 20, 2006 9:55 AM
Subject: [FlyRotary] Re: Injector Switches !!! was Re: Powering fuel
injectors
Thanks for that Ed, I am using the EC2 but I hadn't gone through the
install of it thoroughly yet and wasn't aware of that mode. I'll make
sure
that it's done now.
I follow what you're saying about breakers instead of fuses and I have
to
agree, but following the Bob Nuckolls school of wiring means that the
fuses/breakers should be no more than 6" to a foot from the power source
(battery) and the batteries are behind the rear baggage area and no
where
near the panel. The argument for the fuses to be near the source of
electric power is also valid considering the fuses are there to protect
the
wiring.
Greg
Hi Greg,
Looks like a good electrical system over all. However, I would
not
feel comfortable with fuses in my critical system power line. But, I
see
that you are routing two power sources to each switch of your critical
system which means if one fuse blows due to a transit spike, the other
one, hopefully, will not. Again, this is my own personal bias against
fuses in critical systems - there are arguments to the contrary for
sure.
One thing I did notice, is looking at your injector power switches, I
am
not certain if these are meant to be the same as Tracy Crook's
Injector
disable switches. If they are (and they may not be), I do not see the
connection that automatically grounds the "cold Start" mode in the EC2
when either injector pair are disabled (turned off).
This may be a detail just not shown on the drawing - but it is
crucially
important. If the injector power switch does not have the "cold
start"
grounding provision, then if you ever switch off one of the injector
pairs, your fuel flow will drop approx by 1/2 half. The reason is
that
(with Tracy's recommended switch set up) when you turn off one pair of
injectors , that automatically grounds the "cold start" pin which
causes
the EC2 to double the duration of the PW (Pulse Width) signal to the
remaining injector pair. This in turn doubles the amount of fuel from
the
active pair of injectors. If the "cold start" is not activated (by
automatic grounding of the cold start pin through a DPDT switch) when
an
injector pair is switched off, then the PW signal does NOT double and
the
fuel flow through the one injector pair will only be 1/2 of what the
engine needs.
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.dmack.net/mazda/index.html
----- Original Message ----- From: "Greg@itmack" <greg@itmack.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, October 20, 2006 3:33 AM
Subject: [FlyRotary] Re: Powering fuel injectors
I'm trying to keep the number of switched down as well, I attached a
pdf
with my schematic which is a work in progress for your review.
I have noted that a lot of builders reduce a lot of this complexity
by
just
hanging everything off 1 or 2 fuses which is fine until a fuse blows
and
then everything stops.
Greg RV8 down under
I am using Z-19 from the Aeroelectric Connection as a guide for
wiring
my plane. I would like to power the injectors from the battery
buss.
Looking at Z-19, do I need to install a complete switch and diode
system
for the injectors like is done for the fuel pump and ECU, or can I
tie
on to the fuel pump OR the ECU system after either the switch (add a
separate diode) or after one of the diodes?
There will be the two DPDT switches to disable the primary and
secondary
injectors after this connection.
My panel is becoming somewhat switch festooned and I would like to
keep
more switches to a minimum.
How have you guys accomplished this?
Thanks.
Bill B
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