Test Stator Excitation Winding Resistance; Check Rotor Resistance - Briggs & Stratton 030430 Service And Repair Manual

Test Stator Excitation Winding Resistance

The excitation wires may be colored (red and blue) or
numbered (#2 and #6). Colored excitation wires must not be
confused with the colored power wires. The excitation wires
were disconnect earlier from the brush rectifi er earlier in
Measuring Winding Resistance.
1. Set meter to measure Ohms.
2. Connect the test lead to the stator excitation wires
#2 and #6 (Figure 10). These wires were previously
disconnected from the brush rectifier.
Figure 10
3. Measure the resistance and compare it to the nominal
resistance listed in the back of this manual.
• A reading within the specifications listed is acceptable.
• A reading of infinity or high resistance indicates an
opening in the power winding. Replace the stator.
• A low reading indicates a shorted winding. Replace the
stator.
4. Connect one test lead to a stator power wire. Connect
the other test lead to one of the stator excitation wires.
• A reading of infinity should be measured. If a reading of
infinity is measured and the stator resistance is within
specifications, the stator is functioning properly.
• A reading other than infinity indicates a power winding
shorted to an excitation winding. Replace the stator.
5. Connect one test lead to an excitation wire. Connect the
other test lead to a proper metal ground.
• A reading of infinity should be measured.
• A reading other than infinity indicates a winding shorted
to ground. Replace the stator.

Check Rotor Resistance

1. Set meter to measure Ohms.
2. Connect one test lead to each rotor slip ring (Figure 11).
The slip rings can be accessed through the area where
the brushes were removed. Polarity does not matter.
Figure 11
NOTICE: Do not connect the test lead terminals. Ensure that
each test lead makes a connection to each slip ring.
3. Measure the rotor resistance. Compare it to the nominal
resistance from the specifications listed in the back of
this manual.
• A reading of infinity or a very high resistance indicates
an open circuit or a partially open condition of the rotor
windings.
• A very low resistance indicates a shorted rotor. Replace
the rotor.
• If resistance is within specifications, proceed to Step 4.
4. Connect one test lead to a proper metal ground on the
engine or alternator and the other test lead to either slip
ring.
• A reading of infinity should be measured. If a reading
of infinity is measured and the rotor resistance is within
specifications, the rotor is functioning properly.
• A reading other than infinity indicates a rotor winding
shorted to the rotor shaft. Replace the rotor.
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