Doosan G20P-5, Service Manual

Page: 116 / 306

G424F(FE) Service Manual Chapter 4. Engine Electrical System 114
2. Turn the ignition switch OFF.
3. Disconnect the battery ground cable.
4. Disconnect the alternator output wire from the
alternator “B” terminal.
5. Connect a DC ampere meter (0-100V) between
“B” terminal and the disconnected output wire.
Connect (+) lead wire to the terminal “B” and (-)
lead wire to the disconnected output wire.
NOTE: Do not use clips or equivalent owing to high
current and Use bolts and nuts to tighten each
connecting part securely.
6. Connect a volt meter (0-20V) between “B”
terminal and the ground.
Connect (+) lead wire to the alternator “B”
terminal and (-) lead wire to the proper position.
7. Connect the engine tachometer and then battery
ground cable.
8. Be sure that the hood is opened.
Test
1.
Be sure that voltmeter reading is identified with
battery voltage.
If voltmeter reading is 0V, it means short circuit of
wire between “B” terminal and the battery (-)
terminal, fusible link cut off or ground fault.
2. Turn the headlight ON and start the engine.
3. With the engine running at 2,500 rpm, turn ON the
high beam headlights, place the heater blower
switch at ”HIGH” measure the maximum output
current using a ammeter.
NOTE: This test should be done as soon as
possible to measure the exact maximum current
because output current drops rapidly after starting
the engine.
Result
1.
Ammeter reading should be as same as the load.
If the reading is low even though the alternator
output wire is normal, remove the alternator from
the vehicle and inspect it.
Output current
As same as Elecrical load
NOTE: Output current varies according to electrical
load or temperature of the alternator, so during test,
lack of electrical load causes impossibility of
measuring the rated output current. In this case, turn
on headlight to induce the battery discharging or
turn on other lights to increase the electrical load. If
alternator temperature or ambient temperature is too
high, it is impossible to measure the rated output
current, so prior to re-test, necessarily drop the
temperature.
Ambient temperature
of voltage regulator(
℃
)
Voltage adjust(V)
-30 14.5 ~ 15.4
25 14.3 ~ 14.9
60 14.0 ~ 14.8
90 13.6 ~ 14.6
2. After test, adjust the engine speed at idle and turn
the light and ignition switch OFF.
3. Disconnect the battery ground cable.
4. Disconnect the ammeter and voltmeter.
5. Connect the alternator output lead wire to the
alternator “B” terminal.
6. Connect the battery ground cable.