Re: [Chrysler300] Surprising source of miss in 300 ?
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Re: [Chrysler300] Surprising source of miss in 300 ?





The arc occurs when the contacts separate after the current is already flowing.  It will not occur before they close unless dealing with extraordinarily high voltage.  
----------------------mg


---------- Original Message ----------
From: "Ray Jones 1970hurst@xxxxxxxxx [Chrysler300]" <Chrysler300-noreply@xxxxxxxxxxxxxxx>
To: Fern Rivard <crc@xxxxxxxxxxxx>
Cc: paul <paulholm@xxxxxxxxxxxxx>,  Listsaver 300 Club <Chrysler300@xxxxxxxxxxxxxxx>, Ray Jones <1970hurst@xxxxxxxxx>
Subject: Re: [Chrysler300] Surprising source of miss in 300 ?
Date: Sun, 6 Mar 2016 18:01:48 -0600

 

Thanks Fern, but you miss the point.
The difference is that the switch is just supplying a ground and there is no potential, or need to do work.
Hard to explain, but that's the way my instructors put it,
Think of it as electric welding. Welding is just a dead short that you control, power (voltage) going to ground creating an arc, across a gap, which melts one metal into another to form a bond (weld). That is the maximum definition of potential, being used in a good way.
With power going into a switch, and then on to work and then ground, you create an arc, just as the switch is about to contact the terminal, it jumps across the gap, burning the contacts.
And I can testify that I never replaced any thing with contact points in it on Japanese cars. Not counting the early days of points in Dist.
Not being an engineer, that's the way I understand it and practice seems to bear it out.

What say you Rich? Yes or no?
Ray
 

On Sun, Mar 6, 2016 at 5:30 PM, Fern Rivard <crc@xxxxxxxxxxxx> wrote:
Hi Ray:  It shouldn’t make any difference as you will be drawing the same amount of current thru the switch whether you are key the positive side or the negative side. The real way to prevent any arcing in the switches would be to have a relay carry the load current. I wouldn’t want to have the 12 volt positive sitting at my headlights waiting for the ground to turn them on.  This is just looking for an accident to happen. I’m not a mechanic but have worked on electronics all of my life.
Cheers from Fern
 
 
Sent: Sunday, March 06, 2016 1:03 PM
To: paul
Subject: Re: [Chrysler300] Surprising source of miss in 300 ?
 
 

 

Paul and all;
This has nothing to do with the problem, but just some electric lore to digest.
You mention arcing in the switches. In Japanese cars (worked on them most of my later career)  the switches are switched negatively.
We switch positively. So, what happens is "Potential" arcing. Electricity wants to do work, which is why a short is so bad, NO work.
Even a little mini light bulb, drawing almost no current is work, so all is fine.
So, when we turn a switch, just before the actual contact the current jumps across the space to go to work. This is an arc.
Switched negativity, the work is already in the line so you are merely providing a ground to complete the circuit, no arc, work performed.
In Japanese cars, testing circuits will drive American techs nuts, until they learn this basic fact. Even the head light bulbs will have the current going thru them, awaiting the switch to provide ground so they can light up (work),

If you got this far, go to U-tube and Jay Leno's Garage and look up the Acura NSX video. Awesome car with unbelievable engineering, including separate electric motors for each front wheel and a Armature and field behind the flywheel to provide much more power.

Enjoy, Ray

 
 
On Sun, Mar 6, 2016 at 1:04 PM, paul paulholm@xxxxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:
 

On 03/06/16 13:44, John Grady jkg@xxxxxxxxxxxxxxxxx [Chrysler300] wrote:

> Yes -- they punt you walk . Different kind of problem !!

> Sent from my iPhone

>> On Mar 4, 2016, at 5:13 PM, Michael Moore <mmoore8425@xxxxxxx>
>> wrote:

>> I was about so say I don’t like them because its too hard to
>> trouble shoot a problem based on my experience. But I wonlt say
>> that ! :-)) Mike Moore 300H On Mar 4, 2016, at 1:33 PM, David
>> Schwandt <finsruskw@xxxxxxxxxxxxxxx> wrote:

>> Have you considered going w/a Pertronix?? I did so 20 years ago
>> after distributor problems drove me crazy, some may say I still
>> am!!!

>> -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx
>> [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of 'John Grady'
>> jkg@xxxxxxxxxxxxxxxxx [Chrysler300] Sent: Friday, March 04, 2016
>> 1:37 PM To: 'Michael Moore' Cc: Chrysler300@xxxxxxxxxxxxxxx
>> Subject: RE: [Chrysler300] Surprising source of miss in 300 ?

>> Hi Mike, A bad ballast resistor would stop you ---not burn the
>> points.

snip

>> Dwell going UP (if that is correct data) is points way set too
>> close , Mike ...Burning , you would expect an opening up, Dwell
>> drop, unless cam rub block is rubbing down? And so not opening
>> them. Look at the mechanical action with the cap off... There is
>> chance points were set too close, does not matter who did it, did
>> not open enough, they arc across and burn. Or same thing caused by
>> open capacitor. I had mentioned in an earlier email how critical
>> that setting process is ,and hard to get perfect.

>> Sounds like bad cap..They are intermittent too. Adds to the fun.

In the Telephone industry when they used electromechanical switching,
a serious butt load of relays, contact protection was berry berry
important. All most all ganged relays had a form of capacitor/resister
network on them to aid in controlling arcing, Necessary for long
contact material life. Replacing the contacts on wire spring relays was
a daunting task, usually once in use it was a task that was tried to be
avoided. Once that skill was mastered, the technician that could do it
would usually have a long list of switching centers to go replace
contacts, at least in my experience. (got several nice free lunches
doing that project)

YES, usually once contact wear became noticed, the first thing tried
was replacing the capacitor/resister network. ALTHO I can say that
since they were meant to work a long time, they generally were
not defective, ATT built to last the average lifetime of the hardware.
(No 'Made in China' back then)
If I recall rightly, some of the in use relays usually had an unused
contact pair set aside as a backup in case the working contacts burned
out.

--
--
Paul Holmgren
If you could sum up all you felt about life and crystallize
it in one master insight, you would have said it all, and
you would be dead - Fritz Leiber -

 



--
Ray Jones. Y'all come on down an see us. Ya hear?

 

 



--
Ray Jones. Y'all come on down an see us. Ya hear?

 



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