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MIL-M-17413A(NAVY)
4.2.4.14.2.1 The heat run maybe made immediately following the overload test. Motor load maybe
obtained by maintaining the current torque or watts input corresponding to rated motor horsepower output.
4.2.4.14.2.3 Detail of temperature tests, correction to shutdown. -
4.2.4 .14.3.1 Normal load heat runs on contiuous-duty motors shall be continued until constant
temperatures have been attained in all parts of the motor. For motors having several continuous ratings,
the heat run shall be taken with the rating giving the highest temperature rises. In cases where this can-
not be determined beforehand the motor shall be tested separately for each rating. It shall be considered
that constant temperatures have been reached when at least four consecutive readings taken at 15-minute
intervals show no increase in the temperature of any part of the motor.
4.2.4.14.3.2 The duration of the temperature test of a motor with a short-time or overload require-
ment shall be the time specified for that rating. Intermittent and varying duty motors shall be tested at
the specified duty cycle. In lieu thereof, the motors may be tested as short-time duty motors of sufficient
rating to meet the actual load requirements. The manufacturer shall submit to the bureau or agency con-
cerned evidence that the short-time duty rating used for test purposes is equivalent to the required duty
cycle.
4.2.4.14.3.3 Wherever possible, temperature measurements shall be taken during the progress of
the heat run as well as after shutdown. The highest figures; thus obtained shall be adopted as the
observable temperatures.  Temperature readings shall be obtained for items listed in table V.
4.2.4.14.3.4 Wherever sufficient time has elapsed between the instant of shutdown and the time of
the final temperature measurement to permit the temperature to fall, suitable corrections shall be
applied so as to obtain as nearly as possible the temperature at the instant of shutdown.
4.2.4.15 Hot insulation resistance. -  The insulation resistance and the temperature at which it is
measured shall be taken and recorded immediately following the heat run. (See 4.2.4.11 for details of
test. )
4.2.4.16 Change in speed due to heating. -
4.2.4.16.1 Starting with the motor at approximately room temperature and at rated voltage and load
conditions, the speed in revolutions per minute shall be observed and recorded at the earliest practicable
moment before the field and armature resistances have materially changed in value.
4.2.4.16.2 After the machine temperatures have attained their approximate normal operating valties,
and with the rated load and voltage applied to the motor, the speed in revolutions per minute shall again be
observed and recorded.
4.2.4.16.3 The difference between the full-load cold and full-load hot speeds shall be expressed as
a percentage of the full load hot speed. It shall not exceed the maximum percentage specified in 3.6.13.
4.2.4.17 Permissible variation for rated speed. - The difference between the full-load speed obtained
in 4. 2.4.16.2 and rated speed shall be expressed as a percentage, plus or minus depending upon whether
it is greater than or less than rated speed. It shall not exceed the maximum percentage specified in
3.6.1.24.
4.2.4.18 Radio interference tests. -
4.2.4.18.1 General. -  Where specified in the contract or order (see 6.2), the radio interference
tests shall be conducted in accordance with Specification MIL-I-16910. The contractor shall be responsible
for providing the test equipment, a suitable location for the performance of the tests, the necessary
technical personnel and all facilities for conducting radio interference tests.
38

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