ARMY TM 9-6115-464-34
AIR FORCE TO 35C2-445-2
NAVY NAVFAC P-8-624-34
(e) The generator set contains an overload malfunction indicator. Check and record its indication.
(f) Allow the generator set to cool at rated load for a minimum of 15 minutes.
(9) Repeat steps (c) thru (f) except that the load current is increased to the overload current value in
Phase A only. Phases B and C remain at the rated load current value.
(h) Repeat step (g) except that the load is increased to the overload current value in phase B only.
Phases A and C remain at the rated load value of current.
(i) Repeat step (g) except that the load is increased to the overload current value in phase C only.
Phases A and B remain at the rated load value of current.
d. Results. The data sheets shall show, as a minimum, whether or not the circuit interrupter operated, the
time(s) required for the interrupter to operate, the indication of the malfunction indicator, the overload
condition(s) and the stabilization data. Compare the time(s) requirements of table 4-1.
4-19. CIRCUIT INTERRUPTER TEST (OVER VOLTAGE AND UNDER VOLTAGE).
a. General TO protect the load from generator malfunction (e. g., overvoltage or undervoltage) a circuit
interrupter is connected between the generator voltage reconnection system and the generator output
terminals. A voltage sensing circuit operates the circuit interrupter if an overvoltage or undervoltage condition
occurs and thus protects the load from a generator malfunction.
b. Apparatus. Instrumentation for measuring voltage and frequency shall be as described and illustrated in
MIL–HDBK–705. Resistor(s), galvanometers matching networks, an oscillogram (as described and illustrated in
MIL-HDBK-705, Method 106.1, paragraph 106.1.3) and galvanometers having a minimum flat frequency
response (flat within plus or minus 5 percent) from DC to 3000 Hertz and the voltage divider transformer
network will be required.
c. Procedure I. (Overvoltage).
(1) Preparation for test.
(a) Locate and disconnect the input circuit to the input terminals of the overvoltage protective sensing
circuit and connect the apparatus as illustrated in figure 512.3–I for one voltage connection.
(b) Connect the frequency meter to the output terminals of the generator set.
(2) Test.
(a) Start and operate the set at rated frequency and no load.
(b) Close the switch (see figure 512. 3-I) and use resistance, RI to adjust the voltage to the
overvoltage value specified in table 4-1. The set has provisions for shutdown upon an overvoltage
condition. It will be necessary to temporarily deactivate this provision to permit adjustment of the
overvoltage value. This may be done by activation of the “protective bypass” (Battle Short) switch.
Do not deactivate the circuit interrupter trip circuitry.
(c) Open the switch, reset the overvoltage circuit and adjust the resistance, R2, until voltmeter No. 2
reads rated voltage.
(d) Repeat (b) and (c) to assure that the specified overvoltage and rated voltage settings are correct.
(e) Set the oscillograph chart speed such that the individual waveform peaks are clearly visible. Set the
timing lines to a minimum of 0.01 seconds per line or use a 60 Hertz time trace. Adjust the trace
peak-to-peak amplitude to a minimum of one inch (or 25 millimeters).
4-19
