MIL-DTL-25446E
4.5.3 Temperature transmitter resistance check. The temperature transmitter shall be
immersed to the cap in an agitated liquid bath or other suitable non-gradient apparatus at a
temperature of 200 ° ±0.1 °C (392 °F) for a period sufficient to insure that the transmitter has
stabilized at the test temperature. The test voltage of 1.5 ±0.2 VDC shall be applied across the
temperature transmitter terminals and the temperature transmitter resistance measured. The
measured resistance shall be 116.50 ±0.80 Ω.
4.5.4 Temperature transmitter resistance test. For both qualification and conformance
testing, the temperature transmitter shall be immersed to the cap in an agitated liquid bath or
other suitable non-gradient apparatus at the temperatures shown in 4.5.4.1 and 4.5.4.2 for a
period sufficient to insure that the transmitter has stabilized is at the test temperature. The test
voltage of 1.5 ±0.2 VDC shall be applied across the temperature transmitter terminals and the
transmitter resistance measured. The measured resistance shall be within the tolerances specified
in table II for the test temperature.
4.5.4.1 Qualification testing. The temperature transmitter shall be immersed at each of
the 36 temperatures listed in table II for sufficient time to insure that the temperature transmitter
has stabilized at the test temperature.
4.5.4.2 Conformance testing. For conformance testing, temperature transmitter
resistance testing shall be performed at temperatures of 0 °C (32 °F), 100 °C (212 °F), and
300 °C (572 °F).
a. When the temperature transmitter resistance test is conducted as part of sampling plan
A, tests shall be performed at temperatures of 0 °C (32 °F), 100 °C (212 °F), 200 °C (392 °F),
and 300 °C (572 °F). The temperature tolerance for each measurement shall be ±0.1 °C
(±0.18 °F).
b. When the temperature transmitter resistance test is conducted as part of sampling
plan B, an additional test point of -50 ° ±0.1 °C (-58 ° ±0.18 °F) shall be included.
4.5.5 High temperature exposure. The temperature transmitter shall be inserted in a test
fixture with a temperature at the bottom of the well of 325 ° ±5 °C (617 ° ±9 °F) for a period of
8 hours. The temperature at the bottom of the well shall then be reduced to a temperature of
275 ° ±5 °C (527 ° ±8 °F) and the temperature transmitter shall be subjected to this temperature
for a period of 42 hours. The temperature transmitter shall then be withdrawn from the fixture
and air-cooled to room temperature. The temperature transmitter shall then be subjected to the
spring load test and the measured spring load shall be not less than 2.00 pounds. The
temperature transmitter shall be subjected to the transmitter resistance test at a temperature of
275 °C (527 °F). The measured resistance shall be within the tolerance specified in table II for
the test temperature. The test fixture used shall have an axial temperature gradient of 37.8 °C
(100 °F). The well of the fixture shall be 7.0 inches minimum depth.
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