sults. A battery exercises when it turns over
the starting motor, furnishes energy to the lamps, or operates the a
ignition system. It receives food when it is charged. Proper attention
to the electrical system will result in a correct balance between food
and exercise, or in other words, charge and discharge.

The electrical equipment of a car consists of five principal parts:

1. The Battery.
2. The Ignition System.
3. The Starting Motor.
4. The Generator.
5. The Lighting System.

The normal course of operation of this system is as follows:

Starting. The ignition switch is closed, and connects the ignition
system to the battery. The starting switch is then closed, connecting
the starting motor to the battery. The battery sends a heavy current
through the starting motor, causing the motor to turn over, or "crank"
the engine. The motion of the engine pistons draws a mixture of air
and gasoline vapor into the cylinders. At the proper instant sparks
are made to jump between the points of the spark plugs, igniting the
air and gasoline vapor mixture, forming a large amount of gas. This
gas expands, and in doing so puts the engine into motion. The engine
begins to run under its own power and the starting switch is opened,
since the starting motor has performed the work required of it, and
has nothing further to do as long as the engine runs.

The engine now operates the generator. The generator begins to build
up a voltage as the engine speed increases. When the voltage of the
generator has risen to about 7-7.5, the generator is automatically
connected to the battery by the cutout (also known as reverse-current
relay, cut-out relay, or relay). The voltage of the generator being
higher than that of the battery, the generator sends a current through
the battery, which "charges" the battery. As long As the engine
continues to run above the speed at which the generator develops a
voltage higher than that of the battery, a charging current will
normally flow through the battery. When the ignition switch is opened
the engine can no longer develop any power and consequently stops
running. When the decreasing engine speed causes the generator speed
to drop to a point at which the generator voltage is less than that of
battery, the battery sends a reverse, or discharge current through the
cutout and generator, thereby causing the cutout to open and
disconnect the generator from the battery.

Lights. When the engine is not r