Transformers

[Shannen Durphey]

Bruce Plecan wrote:
> 
> Other than ohms, and ratios, what is there to transformers?.
> Is there a breakdown voltage for insulation?.
> 
> This might seem off the wall but,   If one side of the coil's secondary
> is open (point side), and the other side is connected to a spark
> plug, how is there any flow of electrons with the one side open?.
> 
> With the one side open, but yet connected thru the coil to the+ side
> does that make the return path?.
> 
> The two books I got just say when the points open the field collapses,
> and generates a HV..
> 
> Cheers
> Bruce
Here's what I've noticed.  In DIS systems, if one plug wire
burns open, other plug often fires anyway.  If it's run long
enough it will burn through the internal insulation and
there's no way you can get both plugs to fire.  One of my
books claims 50kv capability from DIS coil.  When one plug
wire burns out that coil is definitely going to make a
return circuit wherever possible.  Length of time before
coil is permanently ruined depends on age of coil, how long
it's been run with open wire, ambient temp.  That insulation
is epoxy.  How long does it take to burn epoxy?  

External coils on TBI pickups often burn through on the
sides.  Look for white spots near the iron frame.  Often
caused by open in coil wire.  Again, insulation breaks down
but timespan and degree varies. 

Have seen integral type HEI run with no ground for the
secondary.  Must find a ground through the module, because
that's usually what I end up replacing first. Then coil is
bad and I find ground strap is missing. 

Think coil secondary is reverse polarity of primary.  To the
spark, the block is positive and center electrode is ground.

Somebody help me out and mention frequency here...

Shannen