TM 9-6115-604-34
NAVFAC P-8-633-34
c. Procedure.
WARNING
To avoid injury to personnel, no electrical component shall be worked on while energized.
When It Is necessary to work In the vicinity of energized equipment, all safety precautions
shall be followed, such as use of rubber blankets for Insulation, use of rubber gloves, and use
of Insulating tools and equipment. All Insulating tools such as rubber gloves and blankets
shall be tested regularly. Disconnect all power before servicing. Residual voltage Is present
at the generator leads even with the regulator turned off . Residual voltages can reach several
hundred volts on this generator. Proper Insulation and Isolation of metering equipment shall
be observed when testing the generator.
(1)
Connect the generator set load terminal to the phase sequence test apparatus for one of the three-phase
voltage connections. Recheck the connections to ensure the L1, L2, and L3 of the generator set are
connected to L1, L2, and L3 of the test apparatus.
(2)
Start and operate the generator set at rated voltage and frequency. The set indicating instruments shall be
sufficient indication of output voltage and frequency.
(3)
Close the circuit interrupter and determine the direction of phase sequence (rotation) by observing the
indicator, or by noting the direction of rotation if a three-phase motor is used. Record the results.
(4)
Phase sequence can also be checked by placing the PHASE SEQUENCE switch, located on the generator
panel, to the GEN position. The 1-2-3 lamp should illuminate.
(5)
Place the AC PWR CKT BKR, located on the generator panel, to the dose position and the PHASE
SEQUENCE switch to the BUS position. The 1-2-3 lamp should illuminate.
d.
Results. The phase sequence (rotation) as indicated by the test shall be checked against the wiring diagram for
L1, L2, and L3.
12-21. PHASE BALANCE (VOLTAGE).
a.
General. Polyphase electrical equipment may not operate properly or may be damaged if the phase voltages of
a polyphase generator differ greatly from each other. Also, large differences between the phase voltages of a
polyphase generator may be an indication that the generator set has been improperly damaged or improperly
repaired.
b.
Apparatus. Arms indicating ac voltmeter, having an accuracy of ±0.1 percent of the reading is required.
c.
Test.
WARNING
To avoid Injury to personnel, no electrical component shall be worked on while energized.
When It Is necessary to work In the vicinity of energized equipment, all safety precautions
shall be followed, such as use of rubber blankets for insulation, use of rubber gloves, and use
of Insulating tools and equipment All Insulating tools such as rubber gloves and blankets
shall be tested regularly. Disconnect all power before servicing. Residual voltage Is present
at the generator leads even with the regulator turned off. Residual voltages can reach several
hundred volts on this generator. Proper Insulation and Isolation of metering equipment shall
be observed when testing the generator.
(1)
Connect the generator set for one of the operating voltages and frequencies.
(2)
Connect the voltmeter to read the ac output.
NOTE
The same voltmeter shall be used to measure all ac output voltages.
(3)
Start and operate the generator set at no load.
12-27
