Kohler 5ECD Service Manual page 46

Grounding electrical equipment. Hazardous voltage can
cause severe injury or death. Electrocution is possible
whenever electricity is present. Ensure you comply with all
applicable codes and standards.
generator set, transfer switch, and related equipment and
electrical circuits. Turn off the main circuit breakers of all
power sources before servicing the equipment. Never contact
electrical leads or appliances when standing in water or on wet
ground because these conditions increase the risk of
electrocution.
Short circuits. Hazardous voltage/current can cause
severe injury or death. Short circuits can cause bodily injury
and/or equipment damage.
connections with tools or jewelry while making adjustments or
repairs. Remove all jewelry before servicing the equipment.
Separate Excitation Procedure
Perform the following procedure to use an external
voltage source to excite the main field (rotor).
1. Disconnect the black FN and FP leads from the
alternator at the SCR module (+) and (--) terminals.
2. Connect a DC ammeter, 10-amp fuse, and a
12-volt automotive battery to the positive (FP) and
negative (FN) brush leads as shown in Figure 5-3.
Note and record the ammeter reading.
Note: The approximate ammeter reading should
be the battery voltage divided by the
specified rotor resistance. See Section 1,
Specifications, for specified rotor resistance
values.
Example:
12 volts (battery voltage)
3.4 ohms (rotor resistance)
3. Start the engine and check that the ammeter
reading remains stable.
reading indicates a shorted rotor. A meter reading
decreasing to zero or an unstable reading
suggests a running open. Refer to Section 5.4,
46 Section 5 Component Testing and Adjustment
Electrically ground the
Do not contact electrical
3.5 amps
=
(rotor current)
An increasing meter
Main Field (Rotor), to test the rotor. If the ammeter
reading is stable, proceed to step 4.
4. Check for AC output across the stator leads; see
Section 5.3, Stator. Compare the readings to the
AC output values
Specifications. If the readings vary considerably, a
faulty stator is likely. Refer to Section 5.3, Stator,
for further information.
5. If this test shows that the rotor and stator are in
good condition, check the wiring and fuses. Check
the SCR module.
Controlled Rectifier (SCR) Module.
controller settings
Section 4, Controller.
1
FN
FP
- +
9 8
1. SCR module
2. FN lead disconnected from SCR
3. FP lead disconnected from SCR
4. 10-amp fuse
5. DC ammeter
6. 12V battery
7. Brushes
8. Slip rings
9. Main field (rotor)
Figure 5-3 Separate Excitation Connections
shown in Section 1,
See Section 4.9, Silicon
Check the
and connections.
2 3 4
5
7
-
+
TP563274
TP-6391 9/08
See
6