Diagnostic Repair Manual 9
Section 3 AC Diagnostic Tests
Introduction
Perform the Diagnostic Tests in this section in
conjunction with the Brushless Troubleshooting
Flowcharts or the Brush Type Troubleshooting
Flowcharts. Test numbers in this section correspond to
numbered tests in the flow charts.
NOTE: Test procedures in this manual are not
necessarily the only methods for diagnosing the condition
of components and circuits. All possible methods that
might be used for system diagnosis have not been
evaluated. If any diagnostic method is used other than
the method presented in this manual, the technician must
be sure that neither personal safety nor product safety,
will be endangered by the procedure or method selected.
NOTE: For graphics of different configurations of stators
and the wire numbers associated with different
components, see appropriate wiring diagrams and
schematics for the generator.
Test 1 – Check No-Load Voltage and
Frequency
Procedure
1. Disconnect or turn OFF all electrical loads
connected to the generator.
2.
Set digital multimeter (DMM) to measure AC voltage.
3. Reset all circuit breakers to ON.
4. Start engine and let stabilize and warm up.
5.
See
Figure 3-1
. Place meter test leads into an
outlet.
Figure 3-1. DMM Test Leads Connected to a 240 VAC
Receptacle
6. Read AC voltage.
7. Connect an AC frequency meter as described in
Step 5.
8. Read AC frequency.
Results
Refer to flow chart.
Test 2 – Check Main Circuit Breaker
Procedure
The generator has circuit breakers located on the control
panel. If outlets are not receiving power, make sure
breakers are set to ON or “Closed”.
If a breaker is suspected to have failed, test as follows:
1. Set DMM to measure resistance.
2. With generator shut down, disconnect all wires
from suspected circuit breaker terminals to prevent
interaction.
3. See Figure 3-2. With the generator shut down,
connect one meter test lead to one terminal of the
breaker and the other meter test lead to the other
termi
nal.
4. Set breaker to ON or “Closed”. The meter should
read CONTINUITY.
5. Set breaker to OFF or “Open”. The meter should
indicate INFINITY.
Figure 3-2. 20/30 Amp Breaker Test Points
Results
1. If circuit breaker tests good, refer to flow chart.
2. If breaker tests bad, replace.
Test 3 – Check Continuity of
Receptacle Panel
General Theory
Continuity of the receptacle panel is important as it
recognizes the receptacle has continuity through the
wiring and is physically connected to the stator. Most
stator winding values are between 0.01 and 0.02 Ohms
of resistance. If a higher than normal value is shown, a
poor connection could be the problem preventing that
receptacle from receiving power.
Procedure
1. Set DMM to measure Resistance.
2. See Figure 3-3. Connect DMM to each receptacle
on unit.
NOTE: Only one outlet on each receptacle needs to be
tested.
No Load Voltage No Load Frequency
223.2 – 256.8 VAC 62.5 – 62.0 Hz
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