REFLECTOR: Using the starter supply(+) wire as a charge wire

[Terry Miles]

Al,

Thanks.  Great points, and I really appreciate your reading my stuff and
responding.  I have a heavy duty starter button from Stein air.  I need to
dbl check its rating and see if it has an internal inductance surpression.
The Skytec guy said to use a 30amp sw too.  I hve a handful of 1N4005's
around here somewhere.  In fact Nuckols shows a pic on his website
http://www.aeroelectric.com/articles/s704inst.jpg

 

That is what you are suggesting, right?  I was going to do a variation on
that...use my heavy switch (direct - no relay) and locate the surpression
diode back on firewall ground bus maybe (if that's OK to have it so far from
the sw?).  Now I am thinking what you did with a 40amp relay makes more
sense and keeps any sparks from jumping switch to switch or elsewhere across
the other stuff in the overhead spaghetti area.   Is it OK to place the
diode anyplace in the run from o'head to starter motor?  

 

Thanks,

Terry

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Al Gietzen
Sent: Saturday, January 27, 2007 12:34 PM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Using the starter supply(+) wire as a charge wire

 

I talked w/ Skytec starters today.  On their web site they talk about an
alternative wiring scheme that eliminates the normal firewall starter
contactor which is required on certified span cans.  I can wire my starter
button directly to the coil/contactor that is bolted to the Skytec starter
instead doing the conventional route of contactor in the nose that then
ports juice to the Skytec contactor and its starter motor.

 

Terry;

 

I don't know about the Skytec, but typically the solenoid/contactor on the
starter takes a significant current, and has a very large in-rush current.
I think you'd would want a switch rated to 30-40 A; with spike suppression,
for reliability.  I used a automotive 40 A relay for the job (also with a
TVS) so I could use a light duty push button up front.

 

Al

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