Yanmar 4LHA-HTP Operation Manual page 643

Chapter 9 Electrical System
4. Alternator
4. Alternator
The alternator serves to keep the battery constantly charg-
ed. It is installed on the cylinder block by a bracket, and is
driven from the V-pulley at the end of the crankshaft by a V-
belt.
The type of alternator used in this engine is ideal for high
speed engines with a wide range of engine speeds. It con-
tains diodes that convert AC to DC, and an IC regulator
that keep the generated voltage constant even when the
engine speed changes.
4-1 Features
The alternator contains a regulator using an IC, and has the
following features.
(1) The IC regulator is self-contained, and has no moving
parts (mechanical contact points). It therefore has
superior features such as freedom from vibration, no
fluctuation of voltage during use, and no need for read-
justment.
Also, it is of the over-heating compensation type and
can automatically adjust the voltage to the most
suitable level depending on the operating temperature.
(2) The regulator is integrated within the alternator to
simplify external wiring.
(3) It is an alternator designed for compactness, lightness
of weight, and high output.
(4) A newly developed U-shaped diode is used to provide
increased reliability
maintenance.
(5) As the alternator is to be installed on board, the follow-
ing measures are taken to provide salt-proofing.
1) The front and rear covers are salt-proofed.
2) Salt-proof paint is applied to the diode.
3) The terminal, where the inboard harness is connected
to the alternator, is nickel plated.
4-3 Characteristics
15,
100
12
80
<
I" r 60
40
3 3
O l
o
ir
3 - 20
and easier checking and
1
Regulated voltage
/
/
- Ou put c urrent for i: J.5V-
/
/
/
/
/
4 6
Speed of alternator (rpm)
4-2 Specifications
Model of alternator
Model of IC regulator
Battery voltage
Nominal output
Earth polarity
Direction of rotation
(viewed from pulley end)
Mass
Rated speed
Operating speed
Speed for 13.5V
Output current at 2 0
Regulated voltage
1
1
8 12
10
9-17
, 4LHA Sen
LR155-20 (HITACHI)
TRIZ-63 (HITACHI)
12V
12V/55A
Negative earth (e)
Clockwise
4.3kg.
5000 rpm
1000 ~ 9000
1000 or less
C over 53A/5000 rpm
o
14.5 ±0.3V (Standard temperature
voltage gradient, -0.01/
14 x i c
C)
o