Matronics Email Lists :: View topic - Magneto Switches and 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

Magneto Switches and Wiring

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

FLYaDIVE(at)aol.com
Guest

Posted: Thu Oct 12, 2006 12:58 am Post subject: Magneto Switches and Wiring

In a message dated 9/14/2006 6:14:29 AM Eastern Standard Time, SMITHBKN(at)aol.com writes:

  	  Quote: 	
		   Listers,

  

 I've read Bob's book and searched the archives but still can't seem to find answers to confirm that my desired approach on magneto and starter wiring will work (or maybe there is a simpler way).

  

 I have two traditional magnetos for an IO-360.  I would like to have a toggle switch for each mag, and a momentary toggle for the starter (with a toggle guard for added protection of inadvertent activation).

  

 I don't fully understand the "impulse" aspect of the magneto.  Could someone help explain such and outline the correct wiring for this setup?

  

 Thanks,

  

 Jeff

	


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

 Jeff:

  

 Did you get a useful answer as yet?

 The idea of dual toggle switches (SPST) is PERFECTLY acceptable.  The switch should be a good quality and physically robust just for S&G's I used a 15 Amp switch ... ONLY because of the solid feel the switch had in opening and closing and that it would function well with gloves on.

  

 Impulse coupling - In this regard there is a lot to say and understand - but, here is the short and simple response:

 1 - If you have dual Mags usually in 99.9% of the cases the LEFT Mag is the impulse Mag.

 2 - For a few extra bucks you can make BOTH mags impulse mags.  It will require:

 Impulse Mag

 Impulse Mag drive gear

 Longer mounting studs (2) 

 Adapter ring 

 Ring gasket 

 Seat gasket

 The advantage of dual impulse mags is more spark to start the engine and much less chance not being able to start when the pawl fails... Double your chances of starting.  

 3 - The Normal spinning of the prop is NOT fast enough to induce an electrical current into the Mag coil to produce a spark. 

 4 - The Normal timing of a Mag is 25 DBTDC and that is not at a proper point for the spark to fire and START the engine.

 5 - The impulse Mag has a Pin and a Pawl.  The Pawl catches on the pin (at LOW RPM's) and cocks back a spring.  When the pawl is released two things happen:

 a> The Spring SNAPS the Mag's spinning Magnet at a much higher speed which induced a voltage into the Mag coil.  More speed equals more spark.

 b> The delayed action of the snap also occurs at TDC which is a better timing location for the starting of the engine.

 6 - Once the engine has started the centrifugal force of the higher spinning RPM throws the pawl to the outside and away from the pin so this disarm the impulse portion of the impulse Mag.

  

 I have dual impulse mags on my O-320.  Only because I was stranded for 3 hours when the impulse Mag failed.

  

 OK, wiring ... Simple ...

 Mag Wiring - ON is OFF and OFF is ON.

 When the Mag switch is DOWN - ON ... YES ... ON.  You are GROUNDING the 'P' Lead of the Mag and this sends the spark created by the Mag to ground and away from the spark plugs.

 When the Mag switch is UP - OFF ... YES ... OFF. The Ground is removed from the 'P' Lead and the Mag is HOT and ready to send a spark to the spark plugs.

  

 When you say "Toggle Guard" I guess you are referring to that fancy RED Plastic cover over the Starter Switch?  Sure that is a good idea.  BUT DON'T put them on the MAG switches ... Only on the Starter Switch.

  

 Hope this helped?

  

  

 Barry

"Chop'd Liver"



"Show them the first time, correct them the second time, kick them the third 

time." 

Yamashiada

- 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