Yanmar YM276 Service Manual page 529

Charaina Circuit 15A
PRECAUTIONS
, - - .
CAUTION: When working on charging circuit, ob-
A
serve the following rules for your safety and preven-
tion of damage t o tractor:
Safety
1. Keep all sparks and flames away from battery. Gas
from banery electrolyte is highly flammable. Also
avoid spilling electrolyte on yourself or on anything
which could be damaged by the sulphuric acid.
2. Avoid sparks when connecting booster battery or
battery chargers. When possible, make l a s t connec-
tion at a point away from banery. Battery charger
shwld
be
turned off before connecting or disconnect-
ing.
3. When connecting battery, always connect ground
cable last. Disconnect ground cable first.
4. When possible, disconnect battery ground cable
before working on electrical system.
PREVENTION OF DAMAGE
1. Before connecting banery cables, be sure that battery
and alternator connections are correct. Reverse po-
larity can cause permanent damage.
-
2. When connecting a booster battery, connect positive
(+I
terminal of booster battery t o positive terminal of
tractor battery. Then connect negative
(-1
terminal
of booster battery t o tractor frame. Reverse polarity
can cause permanent damage.
3. Never run engine with alternator or banery cables
disconnected; doing so might damage alternator.
4. Never short across or g r w n d alternator terminals
unless specifically recommended. Be careful t o pre-
vent grounding alternator wires when disconnected.
5. Never attempt t o polarize an alternator.
DIAGNOSIS AND TESTS
Before testing alternator itself, see if problem is somewhere
else.
.
Check for loose or worn alternator belt.
.
Check for excessive loads, such as add-on lighting.
which might exceed alternator capacity.
.
Ask how tractor is used. Problem might be frequent
starting, with too little running t o recharge battery.
.
Test battery as instructed in Section
05.
Check for a slow drain on battery. Wiih all switches
off, dirconnect banery ground cable and connect a
sensitive ammeter between cable and banery post. If
current exceeds 100 milliamps, see where it is going.
Unplug connectors until you locate the circuit, then
try t o find the problem.
.
Check entire charging circuit for a poor connection.
Problem could be at battery, starter, key switch,
regulator or alternator.
SME2760111a)M YM276and 2 7 6 0
Kinornoto. Printed in Japan