INTRODUCTION TO THE HMMWV - OD1615 - LESSON 4/TASK 1
The alternator is composed of the same basic parts as a direct current (dc)
generator. There is a field that is called a rotor and a generating part
known as the stator. The purpose of the alternator is to produce more power
and operate over a wider speed range than that of a generator. Because of
this, the construction of the functional parts is different. The stator is
the section in which the current is induced.
It is made of a slotted
laminated ring with the conductors placed in the slots.
The current
generated in the windings is transferred to the rest of the system through
three stationary terminals.
One of three different amperage rated alternators can be found on the HMMWV.
One is the 60 amp alternator, which is similar to the alternator used on the
M151. It is mounted on the left side of the engine and is driven by dual
drive belts from the crankshaft pulley. A slotted bracket allows for belt
tension adjustments. The other two alternators are the 100 amp alternator,
found predominantly on the shelter carriers (M998 and M1037), and the 200
amp alternator which is used mainly on the ambulance (M996 and M997).
c. Starter. Any internal combustion engine must be cranked to start it
running on its own. Early automotive vehicles were started manually through
the use of a handcrank. A system for cranking the engine with an electric
motor was developed as automotive technology progressed.
The modern
electric starting system has reduced the task of starting an internal
combustion engine to the turn of a key or the pushing of a button.
The starter may drive the engine through a pinion, or by a dog clutch
attached to the starter armature shaft. The shaft is brought together with
the teeth cut on the rim of the flywheel or with the mating half of the dog
clutch. The drive must be equipped with an overrunning clutch or some other
means of quick disengagement. Owing to limitations of size and capacity of
the battery, a high-speed starter with a high gear reduction is used to
obtain the necessary torque. The great speed reduction required is effected
in the majority of cases by utilizing the flywheel as a driven gear.
In
some instances, the gear is bolted or shrunk on the flywheel, while in
others the gear teeth are
42
Previous Page
