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TACHOMETER
The tachometer
is operated by pulses generated - from anyone of the
al ternator phases.
The pulse fr equency is determined by the rota-
tional speed of the alternator rotor.
The rotor speed is dependent
upon
the
engine
crankshaft
speed
and
the RATIO of
the
alternator
pulley to the cr ankshaft pulley.
The
tachometer
in an
instrument
panel is calibrated by Westerbeke for the standard alternator; if an
optional alternator
(i.e., 90 amp) is used to operate the tachometer,
the
calibration
should
be
checked.
Also,
when
a
tachometer
is
replaced, the new instrument must be calibrated.
CAUTION
WHEN
CALIBRATING
THE
TACHOM-
ETER,
USE
A
PHILLIPS
SCREW-
DRIVER WITH AN INSULATED SHAFT.
1.
Use a motor tester with an RPM indicator, another tachometer or a
strobo-tach to determine the speed of the crankshaft turning.
2.
Remove the plastic plug and flatwasher located on the rear of the
tachometer.
3.
Insert
an
insulated
Phillips
screwdriver
into
the
calibration
control slot and slowly turn counterclockwise to increase the RPM
reading,
clockwise
to
decrease
reading
(direction of
screw as
viewed
from
the
rear
of
the
tachometer
case).
An
accurate
calibration setting is more easily achieved at the higher side of
the dial scale.
4.
Replace plastic plug and flatwasher.
STARTER
The starter is a DC series motor
with a solenoid-operted pinion, which
is smoothly moved by magnetic swi tch
operation into and out of mesh with
the flywheel ring gear.
It is made up roughly of a motor
which generates power, an overrunning
clutch which transmits the torque and
prevents
the
overrunning
after
the
eng ine star ts,
and a magnetic switch
which moves the pinion into mesh with
the
ring
gear
and
sends
the
load
current to the motor.
95
I. Magnetic switch
2. Shift lever
3. Front bracket
4. Over running clutch
5. Stop ring
6. Center bracket
7. Yoke
8. Pole
9. Field coil
10. Armature
II. Brush
12. Rear bracket
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