thanks in advance

 

rotor arms are used inside distributers and direct to voltage to the needed ht lead connected to that point in the distributer cap

as for the ballast risistor im prity sure it holds a charge of some sort and slows down the wairing out time on the points inside the distributer

 

Ballast resistors are used to lower the voltage in the LT circuit after the engine starts ... it's in an attempt to reduce wear and tear of ignition components. Higher voltage is still maintainted during cranking to hopefully make for easier starting.

 

When a ballast resistor is used the ignition coil is rated at a lower voltage i.e 9v on a 12v system.

The resistor limits the voltage on normal running to whatever the coil design voltage is i.e 9v.
When the starter is engaged the resistor is by passed giving the coil effectively a higher voltage, but because the starter causes a volt drop the coil still only gets a little over design volts.

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