Ballast Resistor

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Posted by Jack - Iowa on January 24, 2019 at 08:07:04 [URL] [DELETE] :

In Reply to: 2n runs fine posted by John S on January 24, 2019 at 07:04:01:

Congratulations John!

The purpose of the ballast resistor is to drop the voltage to the coil. It is constructed of a wire with a high temperature coefficient.

When cold, the resistor is quite low allowing maximum voltage to the coil for starting purposes.

It soon warms up which lowers the voltage to the coil and thus reduces the current through it and the heat it must dissipate.

Some coils are built with internal resistance which in effect does the same thing. Those coils generally are marked: NO RESISTOR REQUIRED or something like INTERNAL RESISTOR.

If your coil does not have those markings you likely need the ballast resistor to keep the coil from burning up.

Many years of automobiles were built with a switch section on the starter switch or solenoid which by-passed the ballast resistor for starting. You can do the same thing on your N by holding a quarter across the resistor terminals.

Hope this helps you.

My email is open if you have further questions.


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