4AIR STARTING SYSTEM
AIR STARTING SYSTEM
temperatures below 0C (32F)] should be used with the
The air starting motor is used to turn the engine
flywheel fast enough to get the engine running.
starting system. The maximum pressure for use in the
air starting motor is 1030 kPa (150 psi).
pressures can cause safety problems.
TYPICAL AIR STARTING SYSTEM
1. Air starting motor. 2. Relay valve. 3. Oiler.
TYPICAL AIR START INSTALLATION
The air starting motor can be mounted on either
4. Air start control valve.
side of the engine. Air is normally contained in a storage
tank and the volume of the tank will determine the length
The air from the supply goes to relay valve (2).
of time the engine flywheel can be turned. The storage
The starter control valve (4) is connected to the line
tank must hold this volume of air at 1720 kPa (250 psi)
before the relay valve (2). The flow of air is stopped by
the relay valve (2) until starter control valve (4) is
activated. The air from starter control valve (4) goes to
For engines which do not have heavy loads when
piston (10) behind pinion (8) for the starter. The air
starting, the regulator setting is approximately 690 kPa
pressure on piston (10) puts spring (11) in compression
(100 psi). This setting gives a good relationship between
and puts pinion (8) in engagement with the flywheel gear.
cranking speeds fast enough for easy starting and the
When the pinion is in engagement, air can go out through
length of time the air starting motor can turn the engine
another line to relay valve (2). The air activates relay
flywheel before the air supply is gone.
valve (2) which opens the supply line to the air starting
If the engine has a heavy load which can not be
disconnected during starting, the setting of the air
pressure regulating valve needs to be higher in order to
get high enough speed for easy starting.
The air consumption is directly related to speed;
the air pressure is related to the effort necessary to turn
the engine flywheel. The setting of the air pressure
regulator can be up to 1030 kPa (150 psi), if necessary,
to get the correct cranking speed for a heavily loaded
engine. With the correct setting, the air starting motor
can turn the heavily loaded engine as fast and as long as
it can turn a lightly loaded engine.
AIR STARTING MOTOR
Other air supplies can be used if they have the
5. Air inlet. 6. Vanes. 7. Rotor. 8. Pinion. 9. Gears.
correct pressure and volume. For good life of the air
10 Piston. 11. Piston spring.
starting motor, the supply should be free of dirt and
water. A lubricator with SAE 10 nondetergent oil [for
temperatures above 0C (32F)], or diesel fuel [for