Custom Search
|
|
|
||
 T M 5-685/NAVFAC MO-912
system must rotate (crank) the engine at a speed
(2) Air starting. Some larger engines may use
sufficient to raise the cylinder air charge to the fuel
an air starting system. Compressed air at a pres-
igniting temperature. See figure 3-6.
sure of 250 or 300 psi is delivered to the working
a. Types. Two types of starting systems are avail-
cylinder's combustion chambers during the power
able for the required automatic start-up capability:
stroke. This action results in positive and fast rota-
electric starting and air starting.
tion (cranking). Depending on the manufacturer's
(1) Electric starting. Most small diesel engines
design, compressed air can be delivered to all or
use an electric starting system. This type of system
selected cylinders. This type of system requires an
is generally similar to a starter for an automotive
air compressor and receivers or air bottles for stor-
gasoline engine. Smaller diesel engines use a l2-
age of compressed air.
volt battery-powered system for cranking. Starter
(3) Air starter motor. Pneumatic air starter mo-
and battery systems of 24, 32, and 48 volts are often
tors are highly reliable. Air starter motors develop
used for larger engines. A typical system consists of
enough torque to spin the engine at twice the crank-
storage batteries (as required for voltage output)
ing speed in half the time required by electric
connected in series, a battery charging system, and
starter motors. Compressed air at a pressure of 110
the necessary grounding and connecting cables. See
to 250 psi is stored in storage tanks, regulated to
figure 3-10.
110 psi and piped to the air motor. A check valve
BATTERY CONNECTING C
CABLE TO
CABLE TO GROUND
Figure 3-10. Battery for engine starting system.
3-16
|
 
|
|
|
||
