MIL-DTL-23928G
TABLE IV. Sampling for conformance.
Sample size
Number of panels
Acceptance
Rejection
Normal
Tightened
in inspection lot
number
number
inspection
inspection
2 to 10
All
All
---
---
11 to 15
10
12
0
1
16 to 25
13
15
0
1
26 to 40
17
19
0
1
41 to 65
22
24
0
1
66 to 110
28
31
1
2
111 to 180
35
39
1
2
181 to 300
45
49
2
3
301 to 500
55
60
2
3
501 and over
70
75
3
4
4.4 General examination. Sample equipment shall be subjected to a thorough examination to ascertain that the
material, workmanship, and construction are in conformance with this specification. The fit of parts shall be observed
with particular reference to the interchangeability of such parts as are likely to require replacement during the normal
service life of the equipment and potential malfunctions due to cumulative misalignment of parts. Specific
observation shall be given to the features specified in 3.6 and to the following:
a.
Dimensions.
b.
Creepage and clearance distances.
c.
Alignment of parts. Bolts and screws shall be loosened and tolerances and misalignment of parts checked.
d.
Fit and freedom of operation of circuit breakers.
4.5 Methods of examination and test.
4.5.1 Test conditions. Unless otherwise specified (see 6.2), tests shall be performed under standard ambient test
conditions in accordance with MIL-STD-810.
4.5.1.1 Preparation for test. Preparation for first article inspection tests (see 4.2), which include shock and
vibration, shall consist of installing the maximum number of circuit breakers or a combination of circuit breakers and
simulated components of the type specified in each panel to be tested. When only circuit breakers are installed, NLB
or NQB types may be used in lieu of ALB or AQB. When simulated components are used, there shall be one circuit
breaker installed for every four installed simulated components. The simulated components shall be comparable in
size and weight to the type circuit breakers replaced and the method of mounting shall be similar to that used for the
actual circuit breakers.
4.5.2 Effectiveness of enclosure. Samples shall be tested in accordance with MIL-STD-108 to determine the
effectiveness of enclosure (see 3.5.1).
4.5.3 Temperature rise. The sample shall be subjected to heat testing. The heat testing shall be conducted under
simulated conditions equivalent to normal operating conditions employing maximum rated voltage, maximum rated
load, and rated frequency. Thermocouples (or equivalent temperature sensors) shall be installed on selected bus bar
connection points and terminals to determine maximum temperatures of current carrying parts. Similar sensors shall
be installed approximately 2 inches (50.80 mm) from the top and bottom of the panel to measure the ambient
temperature rise. The heat run shall be conducted continuously until the measured temperatures have remained
constant for 2 hours. Temperature rise shall not exceed the values specified (see 3.5.2).
15
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