ARMY TM 9-6115-464-34
AIR FORCE TO 35C2-445-2
NAVY NAVFAC P-8-624-34
e. Results.
(1) From the oscillograms made in 4-20c, determine and tabulate the time between the application of
the overvoltage and operation of the circuit interrupter for each application of overvoltage.
(2) From the oscillograms made in 4-20d. determine and tabulate the time between the application of
the undervoltage and the operation of the circuit interrupter for each application of undervoltage.
(3) Compare these results with the requirements of table 4-1.
4-20. LOW OIL PRESSURE PROTECTIVE DEVICE TEST.
a. General. Since generator sets frequently operate unattended for tong periods, the engine is equipped with
a low oil pressure protective device. This device shuts down the engine when the oil pressure drops below the
safe limit.
b. Apparatus. The following equipment shall be required to perform this test.
Oil pressure gauge (±1%)
Flexible oil line (or copper tubing)
Regulating valves
Brass fittings.
c. Procedure.
(1) Preparation for test. With the set not operating, remove the protective device tap from the engine
block and reconnect as shown in figure 515.1–I with the protective device and oil pressure gauge in
approximately the same horizontal plane as the protective device tap located on the engine.
(2) Test.
(a) With the bleeder valve closed and the shut-off valve in the oil pressure line open, start and operate
the set at rated speed (use the set instrumentation) and at no load.
(b) Open the bleeder valve slightly to purge air from the system.
(c) Close the bleeder valve and record the oil pressure as indicated on the external gauge.
(d) Almost completely close the shut-off valve.
(e) Slowly open the bleeder valve until the low oil pressure protective device shuts down the engine.
Record the reading of the oil pressure gauge at the point of set shutdown (see figure 515.1-II).
(f) Record operation of the malfunction indicator light.
d. Results. Compare the value of shutdown pressure with the requirement of table 4-1.
4-21. OVERTEMPERATURE PROTECTIVE DEVICE TEST
a. General. The overtemperature device must be capable of protecting the engine in the set against
overheating for any reason.
b. Apparatus Instrumentation for measuring load conditions and set and ambient temperatures shall be as
described and illustrated in MIL-HDBK-705, Method 205.1, Paragraph 205.1.10.
4-21
