WEICHAI WD10 Service Manual - page 137
Service Manual for WD10 Diesel Engine
127
Fault 2: Low charging voltage
Phenomenon
Fault detection
Troubleshooting
Battery is
occasionally
underpowered,
low charging
voltage, and the
voltage declines
markedly once
loaded.
Check whether generator
output power is reasonably
matched with electrical
appliances.
a. Check whether
voltmeter is damaged.
b. Check generator speed.
c. Check the quality and
tensioning situation of
generator belt and
relevant pulley belts.
d. Check generator
pulley.
e. Check whether electric
wires are reasonably
connected, measure the
voltage of generator
and battery.
f. Check whether wires in
charging system are
loose, oxidized and
producing too much
heat, check whether
bolt connections are
loose.
g. Measure output voltage
of generator W/R/AC
terminal (should be
about half of B+
terminal voltage).
h. Check whether battery
charging is normal.
Measure generator B+ terminal voltage,
which should be within 27.8~28.4V, if the
voltage is normal, then it means voltmeter
failure or voltmeter sampling point is in fault,
repair or replace.
a. It is recommended the generator idling
speed should exceed 1600rpm.
b. Generator speed should be 2000rpm and
above, or the voltage should be about 27V
when high power load appliance like air
condition is working
c. Check the quality of generator belt and
relevant pulley belts, for belt involved
severe coking, breakage, deformation or
wear should be replaced.
Tension generator belt and relevant pulley
belts.
ATTENTION: If the to-be replaced belt is
in twin-drive belt system, then the belts
should be replaced together.
d. Tension it if it is loose.
e. If voltage drop is bigger than 1V in heavy
load condition (thin wire results in big
voltage drop), the wire should be replaced.
0~35A S≥6mm
2
35~70A S≥12mm
2
70~100A S≥20mm
2
100~150A S≥25mm
2
If the wire or connector gets too hot in
heavy load condition, then the wire or
connector should be replaced.
f. Oxidized lead foot and the housing that
used to install grounding bolts should be
polished before reassembling.
Retighten the loose nuts and lug plates,
re-plug the loose connectors firmly.
ATTENTION:
Reassembled
or
retightened parts should be run in heavy
load and will be overheat, check whether
the overheat is still there 3~5min later.
g. If there is big difference between terminal
W/R/AC output voltage and normal range
and big voltage drop happened after the
engine loaded, then it means failure in
generator rectifier bridge or stator, repair
or replace.
h. If charging current drops to about 10A
10min later, or charging current reaches to
30-90A for a long time, then the battery is
damaged, repair or replace the battery.