ARMY TM 9-6115-464-34
AIR FORCE TO 35C2-3-445-2
NAVY NAVFAC P-8-624-34
(1) Preparation for test.
(a) Connect the load instrumentation in accordance with the applicable figure of MIL-HDBK-705,
Method 205.1, Paragraph 205.1.10.
(b) Install a thermocouple to measure the same temperature as seen by the protective device sensor.
(a) Start ando perate the generator set at rated voitage, rated frequency (speed), and rated load.
(b) Block the cooling air to the generator set by any suitable means.
(c) Continuously monitor the temperature seen by the thermocouple installed in paragraph 4-22c. (1)
(b) above. Record the temperature at which the overtemperature protective device actuates.
Record the temperature at which the coolant temperature indicator illuminates.
If the engine fails to shutdown when the temperature exceeds the maximum trip value
specified in table 4-1, the test shall be immediately discontinued. Failure to observe
this caution could result in equipment damage.
d. Results. Compare the results with the requirement of table 4-1.
4-22. PHASE SEQUENCE TEST (ROTATION)
a. General. Unless the phase sequence (rotation) of the load terminals of a three-phase generator set is
correct, serious damage or injury could be done to connected equipment and to personnel as a result of
reversed motor rotation or excessive current surges.
b. Apparatus. A phase sequence (rotation) indicator as described and illustrated in MIL-HDBK-705, Method
116.1 or a threephase motor whose direction of operation in relation to phase sequence is known shall be
(1) Connect the generator set load terminals to the applicable test apparatus for one of the set
threephase voltage connections. Recheck the connections to insure that L1, L2 and L3 of the
generator set are connected to L1, L2 and L3 of the test apparatus respectively.
(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 results.
(4) Check the phase sequence (rotation) of the power output of each power receptacle on the generator
set by connecting the applicable test apparatus to the receptacle and repeating steps (1) thru (3)
(5) Repeat steps (a) thru (d) above for all other three-phase voltage output connections of the generator
d. Results. The phase sequence (rotation) as indicated by the test shall be checked against the
requirements of table 4-1.