Motorola Radius CM200 Посібник з монтажу - Сторінка 27

Переглянути онлайн або завантажити pdf Посібник з монтажу для Радіо Motorola Radius CM200. Motorola Radius CM200 36 сторінок. Commercial series

Operation of a Conventional Ignition System

The battery is connected to the primary winding of the coil through the ignition switch. The primary

circuit is returned to the battery through the breaker points, which are bypassed by the condenser.

The points are normally closed. As the cam shaft is rotated by the engine, it's lobes or corners open

and close the points in proper synchronization with the piston in each cylinder.

With the ignition switch on and the breaker points closed, coil primary current builds up at a rate

determined by the coil inductance.

When the breaker points open, primary current decreases and, by self-induction, an electromotive

force is induced in the primary which is many times greater than the battery voltage. The high voltage

inducted in the coil secondary causes a spark across the distributor rotor-to-spark plug wire gap and

then across the spark plug gap for a short interval of time when the breaker points open. The

condenser reduces arcing of the points.

The secondary circuit of the ignition coil, including the distributor rotor gap and the spark gap, is the

main source of ignition interference. The lead inductance and stray capacitance provide a tuned

circuit. Because the discharge of the circuit is through a low resistance (ionized spark gap), the circuit

tends to oscillate. The frequency and amplitude of oscillation vary as current changes in the spark

gap.