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Coil voltage reduction / resistor

  
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Coil voltage reduction / resistor

 
oldchev oldchev
New User | Posts: 48 | Joined: 08/08
Posted: 08/31/08
10:24 AM

My 64 w/283 has been upgraded with new wiring. The intention was to convert (later) to a Pertronix distributor using their coil, etc. which according to them requires 12v, so the distributor ignition wire (to coil) was updated to battery voltage. Since I am understanding the voltage to the coil using points ignition must be approximately 8.5v, I have installed a ballast resistor to reduce voltage to the coil. The voltage to ballast resistor (not originally equipped) is 14.8 volts (almost same as battery) and after resistor is 12.4v to the coil. The higher voltage is still burning my points.
Various ballast resistors located have ohms in range from .6 ohm to 1.85 ohm.
How does the ohms relate to the specific voltage reduction? How may I check the coil for specific value of resistance voltage required?  
I do not know what ohms the currant resistor has likewise the coil, so still need to check that somehow. -Any electrical help appreciated!  

JW454 JW454
Enthusiast | Posts: 345 | Joined: 07/08
Posted: 08/31/08
07:09 PM

I am not an electric wizard, what I can tell you is, the ballast resistor limits the current buildup in the coil to a level the amplifier (points), can safely intercept. If it wasnt for the ballast resistor, the coil primary current could easily build up 10amps., which would blow out the coil in 4-10 hours. Cant think it does any good for the points either. I think the ohm difference in the different resistors is determined by the type of coil you will be useing. If you want a solid answer on this subject, call Jacobs Electronics 1-800-627-8800. They will set you straight.  JW.