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Old 03-27-2012, 05:17 PM   #46 (permalink)
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Originally Posted by mechman600 View Post
Even if this field control module is junk, I only need it to suppress the giant voltage spike when I open the field circuit. Could this not be accomplished by simply wiring a large capacitor with the field?

All this might have ended up being a good thing.
Hi mechman,
A capacitor will make the field winding - capacitor into an oscillator, which will be worse than a single spike.
To suppress the high voltage from coil collapse a diode is placed across the coil so that it conducts the reverse spike and a diode can be placed to conduct the forward spike into a higher voltage, like the battery. For most applications a standard silicon rectifier with high enough voltage and current ratings works fine. You can't reverse the field if you use diodes.
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