Main Field (Rotor); Rotor Continuity And Resistance Tests - Kohler 8.5RES Service Manual

9. Use a megohmmeter to determine whether the
stator is shorted to ground.
a. Apply 500 volts DC to any stator lead and the
stator frame. Perform the megohmmeter test
following the instructions of the megohmmeter
manufacturer.
b. Repeat the test on the other stator leads until
each coil is tested.
Note: A reading of approximately 500 kOhms
(1/2 megohm) and higher indicates a
good stator.
c. Repair or replace the stator if any reading is
less than approximately 500 kOhms. A reading
of less than 500 kOhms indicates deterioration
of the winding insulation and possible current
flow to ground.
Leads
1 and 2
1 and 11
2 and 11
3 and 4
3 and 44
4 and 44
55 and 66
1 and 3, 4, 44, 55, or 66
2 and 3, 4, 44, 55, or 66
3 and 1, 2, 11, 55, or 66
4 and 1, 2, 11, 55, or 66
Any stator lead and ground on stator
housing or frame laminations
Figure 5-6 Continuity Test Results on a Good Stator
42 Section 5 Component Testing and Adjustment

5.4 Main Field (Rotor)

The two-pole rotor creates the magnetic field needed to
produce alternating current in the stator windings.
Before testing, inspect the rotor for visible damage to
pole shoes, insulation, exposed coil windings, and slip
ring surfaces. Rotate the bearing to check for wear, heat
discoloration, or noise.
5.4.1
Continuity
High voltage test. Hazardous voltage can cause severe
Yes
injury or death. Follow the instructions of the test equipment
manufacturer when performing high-voltage tests on the rotor
or stator. An improper test procedure can damage equipment
or lead to generator set failure.
Grounding electrical equipment. Hazardous voltage can
cause severe injury or death. Electrocution is possible
whenever electricity is present.
No No
breakers of all power sources before servicing the equipment.
Configure the installation to electrically ground the generator
set, transfer switch, and related equipment and electrical
circuits to comply with applicable codes and standards. Never
contact electrical leads or appliances when standing in water
or on wet ground because these conditions increase the risk of
electrocution.
Rotor Continuity and Resistance
Tests
WARNING
Hazardous voltage. Moving rotor.
Can cause severe injury or death.
Operate the generator set only when
all guards and electrical enclosures
are in place.
Open the main circuit
TP-6196 5/04