Generac Power Systems GP Series Diagnostic Repair Manual page 35

Table 4-3. Actual Resistance Values
Stator Wire
Winding Number
Power 11 – 22 0.0786 - 0.0914
Power 22 – 44 0.0786 - 0.0914
Sensing 11S – 22 0.0865 - 0.1005
Sensing 22S – 44 0.0865 - 0.1005
Excitation 2 – 6 0.6082 - 0.7069
* Resistance values In ohms at 20 °C. (68 °F.). Actual readings
may vary depending on ambient temperature.
Connect the meter test leads across stator leads
5.
11 and 22.
a. Normal power winding resistance should be
measured.
Connect the meter test leads across stator leads
6.
22 and 44.
a. Normal power winding resistance should be
measured.
See Figure 4-55 for the following steps.
Connect the meter test leads across stator leads
7.
11 (Pin 1) and stator lead 22 (Pin 2) at the 12-pin
alternator connector (CONN3P, female side).
a. Normal power winding resistance should be
measured.
1 2
7 8
Figure 4-55. 12-Pin Alternator Connector (CONN3P),
Female Side
Connect the meter test leads across stator leads 2
8.
(Pin 6) and stator lead 6 (Pin 7) at CONN3P.
a. Normal excitation winding resistance should be
measured.
Connect the meter test leads across stator lead 11
9.
and frame ground.
a. Infinity should be measured.
Connect the meter test leads across stator lead 2
10.
(Pin 6) at CONN3P and frame ground.
a. Infinity should be measured.
Connect the meter test leads across stator leads
11.
Wire 11 and stator lead 2 (Pin 6) at CONN3P.
a. Infinity should be measured.
Results
If the stator fails any step replace stator.
1.
Diagnostic Repair Manual
15.5 kW 18 kW
0.0540 - 0.0628
0.0540 - 0.0628
0.0619 - 0.0719
0.0619 - 0.0719
0.4370 - 0.5078
3 4 5 6
9 10 11 12
015032
If the stator passes all tests refer back to the flow
2.
chart.
Test 8 – Check Load Voltage and
Frequency
Procedure
Perform this test the same as Test 1 but apply a load to
the generator equal to its rated capacity. Check voltage
and frequency with load applied.
Frequency should not drop below 59 Hertz.
Voltage should not drop below 222 VAC.
Results
If voltage and/or frequency drop excessively when
1.
load is applied, refer to flow chart.
If load voltage and frequency are within limits, end
2.
tests.
Test 9 – Check Load Watts and
Amperage
Procedure
Add up the wattages or amperages of all loads powered
by the generator at one time. If desired, a clamp-on
ammeter may be used to measure current flow.
See the Wattage Reference Guide
generator limits.
NOTE: All figures are approximate. See data label on
appliance for wattage requirements.
Results
If unit is overloaded, reduce load.
1.
If load is within limits but frequency and voltage still
2.
drop excessively, refer to flow chart.
Overloading a generator in excess of its rated wattage
capacity can result in damage to the generator and to
connected electrical devices. Observe the following to
prevent overloading unit:
• Add up total wattage of all electrical devices to be
connected at one time. This total should NOT be
greater than the generator's wattage capacity.
•
The rated wattage of lights can be taken from light
bulbs. The rated wattage of tools, appliances and
motors can be found on a data label or decal
affixed to the device.
• If the appliance, tool or motor does not give
wattage, multiply volts times ampere rating to
determine watts (volts x amps = watts).
• Some electric motors, such as induction types,
require about three times more watts of power for
starting than for running. This surge of power lasts
only a few seconds when starting such motors.
Section 4 AC Diagnostic Tests
to determine
29