MG MGB User Manual

THE
ELECTRICAL
SYSTEM
7
N
6.
If.
the
tests
in
5
show
the alternator
to
be operating
Testing—alternator
removed
S■tiSfaCtOF■y,
disconneCt
the
teSt
Circuit
and
14.
Unscrew the
cover
retaining
screws
and
remove
the
reconnect
the alternator
terminal
connector.
cover_
7.
Connect
a
low—range
voltmeter
between
the pOSitiVC
15.
Unsolder the three
stator
connections
from
the
terminals
of the
alternator and
battery.
recti■er pack,
noting
the
connection
positions.
8.
Switch
on
the
headlamps,
start
the engine
and check
[MPORTANTLWMII soldering
or
unsoldering
the
V01tdr0Pgin
the
Charging CiYCUit
as
f0H0W53
connections
to
the
diodes
great
care
must
be
taken
a.
Run
the engine
at
3,300I-P-m.
and
note
the
not to
overheat the
diodes
or
bend
the pins.
During
voltmeter
reading.
the
soldering
operations
the diode pins
should be
b.
Transfer the
voltmeter
connections
to
the
gripped lightly
with
a
pair
of long-nosed pliers
which
negative
terminals
of the
alternator
and battery,
will then
act
as a
thermal shunt,
and
repeat
the
test
in
a.
If
the voltmeter
reading
in
either
of the
tests
exceeds
.2
volts
a
high
resistance
exists
which
must
be
traced
and
remedied.
Removing
9.
The
following
operations,
a
to
d,
are
necessary on
engines
■tted
with
exhaust emission
control
air
pumps.
a.
Disconnect
the
hoses
from
the
air
pump
discharge connections.
Slacken
the
air
pump
mounting
bolt.
c.
Remove
the
air
pump
adjusting
link
bolt from
the
air
pump.
(1.
Slip
the belt
from the
air
pump
pulley and
raise
the
air
pump.
10.
Withdraw
the
terminal block
from
the alternator.
11.
Remove
the adjusting
link bolt
from
the alternator.
12.
Slacken
the
alternator
mounting
bolts,
lower
the
alternator
and slip
the
fan
belt
from
the
alternator
pulley.
.
Fig. N.27
13~
Unscrew
the
alternator mountmg
bOIts
and
remove
Using pliers
as a
thermal shunt when soldering the alternator
the
alternator.
diodes
Alternator
Probable fault
and
_
associateddamage
'Iest
bulb
Temperature
Norse
Output
Glows
at
stand-still,
goes
out at
Higher
than
normal—40
amps.
Live side
output
diode
850
r_.p.m.,
_then
glows
_
approximately
at
3,300
r.p.m.
open-circuit (May damage
rotor
progressively
brighter
as
the
High
Normal
windings
and regulator
output
speed
is
increased.
stage,
overheat brush boxes,and
blow
warning
light).
Light
out
under
all
conditions.
Very.
low
—
1 0
am p
s.
Live
side
output
diode
High
Excessive
approxrmately
at
3,300
r.p.m.
short-circuit. (May
cause
failure
of
assocratedfield
diode).
Glows
at
stand-still, dims
Poorat
low
speed,
slightly
below
Earth side
output
diode
appreciably
at
850
r.p.m.
and
_
normal at
3,300
r.p.m.—32 open-circuit.
gets
progressively
dimmer
as
NO‘mal
Excessrve
amps.
approximately.
speedis
increased.
Glows
at
a
stand-still,
dims
Very
low
at
all
speeds above
Earth
side
output
diode
slightly
at
850
r.p.m.
and
Normal
E
.
e
8
5
0
r.
p.
m.
—
7
amps.
short—circuit
or one
phase
remains
so
throughout speed
Xcessw
approximately.
winding
shorted
to
earth.
range.
V
7 V
Glows
at
stand-still dirns
Lower
than normal—29
amps
Field
diode
'
‘
_
a
-
'
t
shghtly
at
850
r.p.m.
and
a
roximatel
at
3 300
. . .
open
cum“
I
remains
so
throughout,
speed
Normal
Normal
pp y
’
i
p m
range.
V 7
_ r
Glows
at
stand—still, dims
.
V
e
r
y
l
o
w
—
7
a
m p
s
.
Fiem
diode
short-circuit,
appreciably
at
850
r.p.m.
and
Normal
Excessive
approxrrnately
at
3,300
r.p.m.
remains
so as
speedis
increased.
MGB.
lssue7.
25729
'N.29

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English