[AT] grounded coil

Larry D Goss rlgoss at evansville.net
Thu Aug 30 14:45:24 PDT 2007


Yes, I have electronics background.  I started working with electronics --  
for money -- back in 1953.  Trained by the US Air Force in 1960. Wrote the 
first CAD subroutines for electronic schematics for the AEC while working 
for Bendix in 1969,  taught Electronic drafting for better than 30 years, 
etc.  I tuned and repaired Allen electronic organs back in the days of 
vacuum tubes.  Took the NEC sometime in the 70's.

The schematics that I have at hand and available at the computer which show 
a grounded case are from the Kohler Single Cylinder Service Manual ENS-575 
as revised in 5-73.  It shows the CASE of the coil being grounded in Figures 
7-5, and 7-13.  It also shows the case not being grounded in Figure 7-10, 
and it shows the Breakerless ignition with a grounded case in Figure 7-11. 
But I am not going to post them.  It isn't worth my time and trouble.

My response to the first question concerning this was to "be careful" in 
making an absolute statement that the case does not need to be grounded.  I 
still stand by that.  BTW, I am not angered by the diligence that is being 
pursued on this question.  We all have to be vigilant in making sure the 
"facts" that are posted on forums such as this are accurate.

Larry

----- Original Message ----- 
From: "Chris Britton" <c.britton at worldnet.att.net>
To: <at at lists.antique-tractor.com>
Sent: Thursday, August 30, 2007 1:43 PM
Subject: [AT] grounded coil


> Larry.. don't take this follow comment the wrong way.. but do you have any
> electronics background?  Draw out a simple ignition circuit design... your
> 'coil' circuit will have 3 connections.. 2 for the primary and a 3rd for 
> the
> secondary.
>
> Your primary needs power and ground.  Since the points are mounted in the
> distribuitor.. the points are ground.  that just leaves power.. and then 
> the
> secondary line to the plug(s)
>
> About the only thing I can come up with is some older style system that
> might possibly use an impulse pickup and or an old coil box.. not anything
> more modern.. say.. from 1939 and up.
>
> Be specific.. if you've got some circuit schematics.. or can cite an 
> example
> of a modern points based ignition system that uses a coil that is grounded
> .. IE.. the coil container is ground.. and is an integral part of the
> system... post them.  There are at least a couple of us here that wouldn't
> mind seeing them.
>
> I'm envisioning you would need isolation at the points ( from the
> distribuitor, or from the distribuitor from the block? ) to have them
> function as anything other than grounding breaker contacts.
>
> Also.. lets narrow the scope of this down.  I'm also assuming a round can
> coil or similar application that has 2 primary wires and a secondary high
> tension tower.. etc...  Ans is an external unit.. not an integral part of 
> a
> complete unit.. like in a magneto.. etc.  As we are talking about mounting
> it to an engine.. etc..
>
> ( again.. this is not meant to be inflamitory.. or antagonistic.. just
> asking you what you are basing your claims on... we've shown our cards.. 
> now
> it time to call.. )
>
> Soundguy
>
>>From: "Larry D Goss" <rlgoss at evansville.net>
>>Subject: Re: [AT] grounded coil
>>Well, I don't want to get into a rock throwing contest.  Marshall Brain is
>>a
>>nice guy and we're both members of the same club sponsored by NCSU
>>(literally), but everything that appears in his website is not universal.
>>I
>>still stand by my statement that some ignition coils HAVE to be grounded 
>>to
>>operate.  Just because you haven't come across any, doesn't mean they 
>>don't
>>exist or even that they're rare.
>
>>Larry
>
>
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