Checking Electrical Equipment; Checking The Alternator - Kohler KD 425-2 Workshop Manual

52
53
KD425-2 Workshop Manual_cod. ED0053031750_1° ed_ rev. 00
53
Electrical equipment

Checking electrical equipment

1. Make sure that the connections between the voltage
regulator and alternator are correctly made and in good
condition.
2. Disconnect the starter motor wire from the battery terminal
and connect a dc ammeter (fig.50 and 51).
3. Connect a dc voltmeter to the battery terminals (fig.50 and
51).
4. Turn over the engine a few times without load or connect an
80÷100W lamp load across the battery to restrict voltage to
lower than 13V.
5. Accelerate the engine to 3000 rpm. The current shown by
the ammeter must be in line with the values indicated in
figure 52.
6. Disconnect the load from the battery (if it was previously
connected) and keep the engine running at the above
indicated speed for a few minutes, the battery voltage
should slowly increase until it reaches approximately 14.2V.
At the same time the charge current should drop to around
2A in a period of time that depends on the whether the
battery is fully charged or not.
7. If the charging current is absent or is lower than the value
indicated above, proceed by checking the alternator and if
necessary, renewing the voltage regulator.

Checking the alternator

Check:
1. with motor stopped: the continuity of the windings (fig.53)
by connecting an ohmmeter and ensuring that resistance is
zero, and the insulation between the windings and ground
(fig. 54) by ensuring that the ohmmeter gives a reading of
infinite resistance. If these readings are not obtained the
stator must be renewed.
2. with motor running: use a multitester to check the charge
current between the two yellow wires. Bring the engine up to
3000 rpm - the multitester should give a reading of 35V.
If the values are more than 10V below this value, the rotor is
de-magnetized and the alternator must be renewed.
Important
1. The alternator will not deliver current when the yellow wires
are disconnected.
2. The alternator will burn out if the yellow wires are connected
to ground.
3. The voltage regulator may be damaged if the ground
connection or other circuit connections are not made
properly.
4.The alternator and the voltage regulator will burn out
instantly if the battery connections are inverted.
6
- 37 -