ALTERNATOR
Models AC5,
HAC,
15ACR and 17 ACR
1. Precautions
The
diodes
in
the
alternator function
as
one-way· valves
and
the
transistors
in the
regulator/control
box operate
as fast switches. Both are
accurate
and sensitive.
They
do
not
wear
out
and seldom require adjustment,
but
because they are sensitive
to
voltage changes and
high
temperature, the following precautions are vital to
prevent them from being destroyed.
(a)
DO
NOT
disconnect
the battery whilst the
engine
is running. This will cause a voltage surge in the
alternator
charging
system
that
will
immediately
ruin the
diodes
or
transistors.
(b)
DO
NOT
disconnect
a lead
without
first
stopping
the
engine
and turning all
electrical
switches
to
the
off
position.
(c)
DO
NOT cause a short
circuit
by
connecting leads
to
incorrect
terminals. Always identify a lead to its
correct
terminal. A short
circuit
or
wrong con-
nection giving reverse polarity will immediately
and permanently ruin transistors
or
diodes.
(d)
DO
NOT
connect
a battery
into
the system
without
checking
for
correct
polarity
and voltage.
(e)
DO
NOT
"flash"
connections
to
check
for
current
flow. No
matter
how
brief
the
contact
the tran-
sistors may be ruined.
2. Maintenance
The
alternator
charging
system
will
normally
require
very little attention, but it should be
kept
free from
build-up of dirt, and a
check
made
if it
fails
to
keep
the
battery charged.
(a)
Regularly
inspect
the
driving
belts
for
wear and
correct
tension. It is
important
to
ensure
that
all
belts on a multiple
belt
drive
have equal
tension
and are each carrying
their
share of the load.
Slack
belts
will
wear
rapidly
and cause
slip
which
will
not drive the
alternator
at the required speed.
Drive belts
which
are
too
tight
impose severe
side
thrust on the
alternator
bearings
and shorten
their
life.
Periodically
ensure
that
the
alternator
is
correctly
aligned
to
the drive.
(b)
Do
not
replace
faulty belts
individually
in a mUlti-
belt system. A
complete
matched set
of
drive
belts
must always be used.
(c)
Keep the
alternator
clean
with
a
cloth
moistened in
kerosene
or
cleaning
fluids. Ensure that
ventilation
slots and
air
spaces are
clear
and
unobstructed.
SECTION Q
Electrical Equipment
(d)
Remove any
dirt
accumulated
on the
regulator/
control
box housing, and
ensure
that
cooling
air
can pass freely over the casing.
3.
Fault Finding
on
AC5
The AC 5
alternator
is
so
designed
that
a
flow
of
current
indicated
either
by
the
extinguishing
of
the
warning
light,
or
as shown on the ammeter, is
suffiicient
evidence that the system is in
proper
working
order.
Therefore, no open
circuit,
voltage
or
current
output
checks
should be performed in the
installation
UN-
LESS:-
(a)
The warning
light
fails
to
illuminate
when
the
generator
is
stationary, and the
switch
is
closed
OR fails
to
become
extinguished
when the alter-
nator
is running.
(b)
No
charging
current
is
shown
on ammeter.
(c)
The battery is flat.
(d)
The
battery is
"boiling",
indicating
loss of
voltage
control.
If any
of
the above symptoms
occur,
the
procedure
in-
dicated
below
should be
followed.
(a)
Connect
a
good
quality
moving
coil
voltmeter
0-50
volts range across the battery
or
regulator
negative terminal, and one
of
the three
positive
terminals
marked LO, MED, HI.
Disconnect
alter-
nator
output
terminal. Fit a
good
quality
moving
coil
0 - 100
amp
ammeter
in series
with
the
alternator terminal and
output
lead.
The
battery
should
be
in
a
charged
condition.
(b)
Close the
warning
light
switch
(master
electric
switch
on
dashboard)
when the
warning
lamp
should
light
up.
(c)
Switch
on a
10-15
amperes load such as lights,
etc.
for
fifteen minutes.
(d)
Start
engine
and run
at
fast idle speed
with
fans,
etc,
for
fifteen minutes.
1.
The
warning
light
should
go
out.
2.
The
ammeter
records
a small charge depen-
dant
on
engine
speed.
(e)
Increase
engine
speed
momentarily
to
maximum
speed, when the
charging
current
should be
about
30
Amperes
for
24 Volt, and 53 Amperes
for
12
volt
systems.
(f)
With the
alternator
running
at
approximately
half
speed,
(engine
speed about 1,500
rev/min)
switch
off
electrical
load.
Depending
on the
connection
selected
for
the
positive
sensing
wire
LO; MED
or
HI,
the
voltage
should rise
to
between
26
and
28 volts
on
24
volt
systems and
13-14
volts on 12
volt
systems
and
then
(emain constant.
At
the
same
time
the
current
reading should
drop
appreciably.
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