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From: "Greg" <greg@itmack.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1489409@logan.com>
Subject: Re: [FlyRotary] Re: Injector Switches !!! was  Re: Powering fuel injectors
Date: Sat, 21 Oct 2006 08:01:48 +1000
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The power to these circuits are independant to the contactors. It's designed
that way so that in the case of alternator failure the conactors are
switched off and the engine still has power directly from the batteries.

John has a valid point that probably most aircraft are wired with long runs
to the fuses.  The spam cans do this so the fuses are accessable but from an
electrical point of view it's incorrect.  That is why there are dual fuses
for critical equipment.

Greg


>I believe that the wire from the battery to behind the panel is 'protected'
>by the use of a contactor that will break the circuit when you throw the
>switch. The 'six inch' recommendation is for a wire that is not removable
>from the circuit by either the contactor or a fuse/breaker.
>
> Bill Schertz
> KIS Cruiser # 4045
> ----- Original Message ----- 
> From: "John Downing" <downing.j@sbcglobal.net>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Friday, October 20, 2006 12:24 PM
> Subject: [FlyRotary] Re: Injector Switches !!! was Re: Powering fuel
> injectors
>
>
>> Greg;  If the CB's are to only be 6" to 1' from the battery, there are
>> alot
>> of old Pipers flying with the battery behind the seats and the CB;s on
>> the
>> panel, which have a condition.  My Tri-Pacer is 45 years old and it does
>> not
>> know the difference.  JohnD
>> ----- 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
>>> >>>
>>> >>>
>>> >>> --
>>> >>> Homepage:  http://www.flyrotary.com/
>>> >>> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>>> >>>
>>> >>>
>>> >>
>>> >
>>> >
>>>
>>> --------------------------------------------------------------------------
>> ------
>>> >
>>> >
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>>> >>
>>> >
>>> >
>>> >
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>>> >
>>> >
>>>
>>>
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>>
>>
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>
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