In a message dated 98-08-09 08:36:13 EDT, hjillson@argolink.net writes:
> The only thing anyone has left out that I can think
> of is that the coil, being an auto-transformer is indead polarity
sensitive,
> seeing as how the coils of the transformer are wound in oposite directions
> for positive and negative ground.
Harlan,
Good point! This creates a bit of a conundrum, though. They are polarity
sensitive in that the output polarity depends on the input polarity, and they
are polarity sensitive in that a positive ground coil is constructed
differently than a negative ground coil. They are not polarity sensitive in
that when connected to a spark gap on the workbench, either type of coil will
produce a spark, regardless of input polarity. In one case, the spark will
jump from point A to point B, and in the other, will jump from point B to
point A, but the same spark will be produced either way.
This is not true when the coil is operating in a real engine - the spark
produced is weaker if the polarity is not correct, but that is not a function
of the coil, per se, but a function of the spark plug characteristics.
Normally, when I think of something being polarity sensitive, I think of
something that will work only if it is connected the right way, and will not
work, or will be damaged, if connected the wrong way. Of course, this begs the
definition of what the term "will work" means. 80% effective? 90%? 99.99%?
Hmmm. Perhaps we need to not use the term "polarity sensitive" at all, but
what should we replace it with?
> About the only thing I can think of on the plugs is that the polarity
(hence
> direction of current flow) will affect which element of the plug is going
to
> pit , the electrode or the tang.
Another good point!
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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