MG MGB User Manual

THE
ELECTRICAL
SYSTEM
N
Section N.
26
ALTERNATOR
(Lucas
Type
16ACR)
The
construction
of the model
16ACR
alternator
is
similar
to
the 16AC
as
illustrated
in
Fig. N.25,
except
that
a
voltage regulator of
micro-circuit construction is
incorporated
on
the slip-ring end
casing
(see
Fig.
N29).
The
procedure
given
for
removing, testing,
and dismantling the
16AC alternator
in
Section N.25,
operations
9
to
36,
should be followed. For regulator removal
see
operations
17
to
18
of
this Section.
Testing in position
OUTPUT
TEST
1.
Check that the fan belt
is
correctly
tensioned and that
all charging
circuit
electrical
connections
are secure.
2.
Run
the
engine
at
fast
idle speed until normal
operating
temperature
is
reached.
3.
Ensure that the battery
is
fully charged; if
not,
fit
a
slave battery.
4.
Disconnect
alternator.
5.
Switch
on
the
ignition
and
connect
a
voltmeter,
negative
to
earth
positive
lead
to
each
cable
connector
tag
of the
two connector
blocks
in
turn.
If
battery
voltage
is
not
registered
at
any
cable, locate
and
remedy the fault.
6.
Remove the alternator end
cover.
7. Bridge the regulator
green
connector
‘F’
to
earth
(see
Fig.
N29).
8. Refit the three-way
connector
block
to
the
alternator.
Connect
an
ammeter
in series
with
the
positive
lead of
the
two-way
connector
block
and the
positive
output
tag
of the
alternator.
9. Start
the
engine
and
run
at
3,300
r.p.m.
The
ammeter
should
read
34
amps.
If
the
correct
alternator
output
cannot
be obtained, replace
or
service the alternator.
both
connector
blocks from
the
REGULATOR TEST
10.
Disconnect the
bridge from the regulator
green
connector
‘F’ and
earth.
11.
Connect
a
voltmeter
across
the
battery terminals.
Start the
engine
and
run
at
3,300
r.p.m.
If
the
ammeter
reads
zero,
the regulator
pack
must
be
replaced.
MGB.
Issue
7. 25729
12. Adjust the
engine speed
until the
ammeter
reading
falls
below
10
amps.
The
voltmeter
should
read
14.0
to
14.4 volts.
If the
voltmeter
reading
is
not
within
the
limits
stated,
a
faulty
regulator
or
high
resistance
in
the
charging
circuit cables
is indicated.
Re-connect
the cables.
CHARGING
CIRCUIT
RESISTANCE
TEST
13. Connect
a
voltmeter
between the
positive terminal of
the alternator and
the
positive
terminal of the
battery.
14. Start
the
engine,
switch
on
the headlamps,
and
run
the
engine
at
3,300
r.p.m.
The
voltmeter
reading
should
not
exceed .5 volts.
15. Transfer
the
voltmeter
connections
to
the
negative
terminals
of
the
alternator
and
battery.
Run
the
engine
at
3,300
r.p.m.
The
voltmeter
reading should
not
exceed
.25 volt.
If
the
readings
in
14
and 15
are
in
excess
of
that
stated, the
charging
circuit has
developed
a
high-resistance
fault
which
must
be
traced
and
remedied.
16. If the
charging
circuit
resistance
test
is
satisfactory,
the failure
is
due
to
the
regulator
pack
and the
alternator
must
be replaced
or
removed for
overhaul.
Removing
the
regulator
17. Remove
the
alternator.
18.
Remove
the
moulded
end
cover,
and
identify
the
type
of
regulator
pack ■tted;
the
8TR—type
has
two
short
mounting
screws
at
each
end,
while
the
llTR
type
has
a
single
longer
one,
with
a spacer,
screwed
into
the
top
lug
of
the
brush
box
moulding
only.
Both
type
have
two
legs
which
locate
in
the
brush
box
moulding.
Disconnect
the
coloured
tag
lead
connectors
from
the
bruch
box,
(1,
2 and
3)
and
detach
the
black (earth)
lead (4),
after
removing
the
lower
mounting
screw
(8TR)
or
one
of the
brush
box
retaining
screws
(6)
(1
1TR).
Remove
the
remaining
screw
(5)
securing
the
regulator
pack.
Collect
the
spacer
(7),
(1
lTR only).
M0693
Fig.
N29
The in-built
regulator
connections, showing 8TR (B) and
(A)
llTR
type
of
regulator units
1.
Battery
+
(B+).
2.
Positive
(+).
3.
Field (F).
4.
Negative
earth (—).
5. Brush
box
retaining
screw.
6.
Upper
mounting
screw.
7. Spacer(llTR only).
N3
1

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English