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PH3300i SM, Rev. 2017-01-20
4.13 Voltage Regulator Testing
The voltage regulator provides three different isolated voltage sources. The first is the charging
voltage for the 12V starting battery, which uses the negative battery terminal and chassis ground as
its ground reference. The second is the 12VDC output for the control panel, which also uses chassis
ground as a ground reference. The third voltage is the charging voltage for the 3.6V Li-ion batteries,
which uses the black wire from the voltage regulator as a ground reference. In the following tests it is
important to measure the voltages between the wires designated in the test procedures. If chassis
ground is used as a ground reference in every test, then the voltage reading for the Li-ion battery
charging voltage, and the oil alarm signal, will be false readings.
1. To access the voltage regulator, follow steps 1-7 in (section 5.1.1). After conducting the
voltage regulator tests, reassembly using the steps in the reverse order.
2. With the generator running, unplug the stator low voltage winding from the voltage regulator.
Measure the voltage between the blue wires (Fig. 29). The voltage should be 16-20VAC. If
the voltage is good, reconnect the stator and voltage regulator and continue the test. If the
voltage does not fall within this range then replace the stator (section 5.9.2).
3. With the generator running and all voltage regulator connections connected, perform the
following steps:
a. Measure the starting battery charging voltage from the voltage regulator 9-pin connector
(Fig. 30). Put the voltmeter positive test lead on the red wire, and the negative test lead
on the yellow/green wire. The voltage should be 12.0-14.5 VDC, depending on the
condition of the starting battery. If the voltage does not fall within this range, replace the
voltage regulator.
b. Measure the control panel DC output voltage from the voltage regulator 9-pin connector.
Put the voltmeter positive test lead on the red/black wire, and the negative test lead on
the yellow/green wire. The voltage should be 13-15 VDC. If the voltage does not fall
within this range, replace the voltage regulator.
c. Measure the Li-ion battery charging voltage from the voltage regulator 9-pin connector.
Put the voltmeter positive test lead on the red/white wire, and the negative test lead on
the black wire. The voltage should be 3.7-4.2VDC, depending on the condition of the
Li-ion batteries. If the voltage does not fall within this range, replace the voltage regulator.
4. With the engine running, disconnect the low oil sensor connector to test the voltage regulator
low oil sensor response. Leave the 9-pin and stator connector connected. Put the voltmeter
positive test lead on the pink wire, and the negative test lead on the black wire of the 9-pin
connector. Using a jumper wire connect the white wire from the voltage regulator low oil
sensor connector to the engine block. The voltmeter should change from 0VDC to
12.5-14.5VDC, and the engine should die. If neither of these things happens, replace the
voltage regulator. If the voltage changes, but the engine does not die, then look for a break or
short in the pink wire between the voltage regulator and the ignition/indicator module on the
control panel. If the pink wire has good continuity, but the engine still does not die and/or the
low oil light does not illuminate when the white wire is grounded, replace the ignition/indicator
module.
9-pin Connector To Wiring
Harness
To Low Oil
Sensor
To Stator
Fig. 30
Low
Voltage
Windings
from
To the
Voltage
Regulator
Fig. 29