Chris Lillja writes:
>The switching transistor in the Pertronix is designed to operate with
>a coil with a primary impedance of a certain range. If the coil's
>impedance is too low, too much current flows through the switching
>transistor exceeding its heat dissipation rating....result: one
>cooked transistor... one dead Pertronix.....
>I learned this from converting my Norton to Boyer EI... 'ya gotta use
>the right coils or the thing just gets too hot and dies......
>This was also discussed in the Pertronix documentation when I
>intalled it on my 4A....
>"Still ride in triumph over all mischance..." - Shakespeare
>Chris Lillja
>TR4A
>Norton Commando
>Spit MKIV
Cheap design. Any designer who isn't hamstrung by the accounting
department would include a current limiting circuit to shut the
transistor off if the current gets too high. This protects against
misapplication and errant short circuits. I traced out a Japanese
unit once that included current sense and associated circuitry to
shut down the unit. If you are like me (that's a scary thought)
you would rather have the ignition system resume operation after
the problem is fixed than to have to replace the ignition system
too. I guess that is the price you pay for a unit that fits under
the distributor cap.
"95 was the route you was on, not the speed limit sign" Jim Croche
Dave Massey
TR6 (2@)
TR7
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