Matronics Email Lists :: View topic - Impulse Coupled Mag/Elec Ignition Wiring

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Impulse Coupled Mag/Elec Ignition Wiring

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

jjflyboy(at)gmail.com
Guest

Posted: Sun Feb 12, 2012 1:29 pm Post subject: Impulse Coupled Mag/Elec Ignition Wiring

Hi Bob,

I wired the electrical system on my RV3 per Z-11 and installed the two S-700 toggle switches for the magnetos/starter.  I recently discovered that that my engine (O-320 D2J) has two impulse coupled magnetos, not one as I thought initially, and they are both shot so I am considering replacing one magneto and replacing the other with a LSE Plasma III electronic ignition.  Would it be be better to replace the one mag with an impulse coupled mag rather than go to a non-impulse coupled one?  If so, how would that system be wired?  I see Figure Z-27 shows how to wire up a non-impulse coupled mag and one electronic ignition, but does not show the wiring if that mag were impulsed coupled.  Having one IC mag would allow me the advantage of starting the engine on that mag should I lose the electronic ignition.  I could go to a full electronic system, but feel there is an advantage to keeping one mag because of having the different failure modes.  Also, not sure if there is any difference in how an IC mag is driven by the engine such that it could, if desired, be replaced by a non IC mag.  The mags I have now are both Slick 4251s with left hand rotation.  Thanks 



Jerry

  [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Mon Feb 13, 2012 5:14 am Post subject: Impulse Coupled Mag/Elec Ignition Wiring

2/13/2012



Hello Jerry, You wrote:



1) "Would it be be better to replace the one mag with an impulse coupled mag

rather than go to a non-impulse coupled one?"



I think that it would be better not only for the reasons that you cite later 

in your posting, but also easier since you would keep the same gearing and 

magneto stack up that you have on your engine now.



2) "Also, not sure if there is any difference in how an IC mag is driven by 

the engine

such that it could, if desired, be replaced by a non IC mag."



Yes, there is a difference. The IC mag drive arrangement is longer than the 

drive arrangement on a non IC mag to allow space for the impulse coupleing 

so there is an adapter required between the IC mag and the engine accessory 

drive case for the IC mag that is not required for the non IC mag. Examine 

your engine carefully and you will see this adapter (extension) between your 

engine accessory drive case and the magnetos. That adapter is removed for 

the non IC mag.



3) "......they are both shot so I am considering replacing one

magneto and replacing the other with a LSE Plasma III electronic ignition."



Have you considered going with a P mag for replacing one (or both) of your 

present mags.



http://www.emagair.com/P-MAGII.htm



'OC' Baker Says: "The best investment we can make is the time and effort to 

gather and understand knowledge."



==========================================================

Time: 01:29:02 PM PST US

Subject: Impulse Coupled Mag/Elec Ignition Wiring

From: Jerry Jerome <jjflyboy(at)gmail.com>



Hi Bob,



I wired the electrical system on my RV3 per Z-11 and installed the two

S-700 toggle switches for the magnetos/starter.  I recently discovered that

that my engine (O-320 D2J) has two impulse coupled magnetos, not one as I

thought initially, and they are both shot so I am considering replacing one

magneto and replacing the other with a LSE Plasma III electronic ignition.

 Would it be be better to replace the one mag with an impulse coupled mag

rather than go to a non-impulse coupled one?  If so, how would that system

be wired?  I see Figure Z-27 shows how to wire up a non-impulse coupled mag

and one electronic ignition, but does not show the wiring if that mag were

impulsed coupled.  Having one IC mag would allow me the advantage of

starting the engine on that mag should I lose the electronic ignition.  I

could go to a full electronic system, but feel there is an advantage to

keeping one mag because of having the different failure modes.  Also, not

sure if there is any difference in how an IC mag is driven by the engine

such that it could, if desired, be replaced by a non IC mag.  The mags I

have now are both Slick 4251s with left hand rotation.  Thanks



Jerry

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Feb 13, 2012 1:07 pm Post subject: Impulse Coupled Mag/Elec Ignition Wiring

At 02:40 PM 2/13/2012, you wrote:

Jerry,



I'll let Bob and others address the wiring, but thought I'd throw in 

my two cents on the mag/EI combination.



I have an 0-320 like you and I chose an impulse coupled Slick mag on 

the left side, and a Jeff Rose ElectroAir EI system on the right. The 

benefits are the hotter firing EI system in cruise, with a 

conventional mag to get me home if the electrical system and/or the 

EI fail. Additionally, an impulse coupled mag is necessary for starts 

when the EI is not desirable or available. One gotcha, however. My 

ElectroAir EI is susceptible to a low voltage situation, thus it 

usually won't fire with the low voltage caused by the current draw 

when my SkyTec starter is engaged. Of course, the EI tends to fire as 

soon as the start switch is released with the possibility of a 

kickback. I'm not sure if the same situation is true for other EI 

systems, but it is something to check out. As recommended by Jeff 

Rose, I start my engine with the impulse mag on and the EI off. It 

has always started within the first couple of blades, hot or cold.



    I am pretty certain that modern incarnations

    of the electronic ignition are not so afflicted.

    Certainly a LSE system operates down to 6 volts

    or so. Even if the system tends to start off on the

    wrong foot during high inrush from a PM starter

    motor, one can always separate the starter and

    ignition power/up by a second or so. Starter inrush

    is over in 100 milliseconds so if you hit the start

    button and then power up the ignition after the first

    blade passage, the system integration snafu can be

    side-stepped. But I would sure want to analyze the

    cranking system as well to make sure you're not

    tossing away useful volts that could be recovered

    by resizing or connection of wires.



    If there are any working magnetos, then one

    could certainly consider 'using them up' before

    installing dual electronic ignition. Z-13/8 with

    the ignition system driven by their own fuse from

    the battery bus is pretty much bullet proof. One

    could also consider the diode isolated, second

    battery for the #2 ignition as described by LSE.



    In any case, there are no compelling reasons to

    use any magnetos except that you have a resource

    that goes wasted if you take working mags off the

    airplane.



    Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

longg(at)pjm.com
Guest

Posted: Mon Feb 13, 2012 1:33 pm Post subject: Impulse Coupled Mag/Elec Ignition Wiring

I have a Lightspeed/IM-Mag setup and start with both on. My airplane starts like my car. That's suits me just fine. I've tried it both ways, mag only and IE only. Both work fine. When the LSE starts it uses slightly more advanced timing.



I've never had kickback. If the fuel is flowing and the correct pressure is there, it will fire. LSE or Slick or either or both. I've sat by while Cirrus and Cessna sit there and crank, crank, crank. I never have such issues.



Same procedure for hot start except full throttle and mixture out until it fires. Gotta be quick to get the throttle back. I normally run the boost pump a few seconds to get the boiled gas out of the line first. 



Lycoming IO-360.



Glenn



--

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum