MIL-DTL-5846D
solution of salt water at a temperature of 25° C to a point 5 inches from each end of the
insulations for a period of 20 hours. Following this period, a potential of 350v rms at a
commercial frequency shall be applied to the specimen. The potential shall be applied to
the specimen through grounding the outer surface of the insulation by immersion in the
salt solution at not over 30° C and the voltage applied between each conductor and
ground. The wire shall be capable of withstanding this potential for 5 minutes without
breakdown. (see 3.4.1)
4.3.5 Insulation resistance. The samples of wire subjected to the dielectric strength test
shall then be subjected to the insulation resistance test. Insulation resistance measurement
shall be made with a mega ohm bridge or with a galvanometer and a suitable source of
direct current. The measurement shall be made with the specimen immersed in a
saturated solution of salt water, at a temperature of 25° C, to a point 6 inches from each
end of the insulation. The insulation resistance shall be determined between each
conductor and ground after 1 minute electrification with a potential of not less than 200
or not greater than 500 V dc. The insulation resistance of the finished wire 1,000 feet in
length shall be determined as follows: During this test, the temperature of the wire shall
be as nearly uniform as practicable. The measured insulation resistance shall be corrected
to a reference temperature of 15.5° C by multiplying the measured value of insulation
resistance by a coefficient corresponding to the temperature of the measurement. These
temperature coefficients are shown in Table VIII. For temperature values between those
tabulated, the coefficient for the next higher temperature shall be used when above 15.5°
C, and that of the next lower temperature shall be used when below 15.5° C. For
approved insulating materials possessing temperature coefficients not within the limits set
by this reference characteristic, the values applicable thereto may be used when
specifically approved by the procuring activity. (see 3.4.2)
TABLE VIII. Temperature coefficients.
Temperature
Temperature
Temperature
Degrees F
Degrees C
Coefficients
of Insulation
32
0.0
0.032
1.7
0.047
35
38
3.3
0.071
41
5.0
0.098
44
6.7
0.140
0.25
47
8.3
10.0
0.29
50
53
11.7
0.45
56
13.3
0.78
0.91
59
15.0
19
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business