MIL-DTL-28788C
MIL-STD-202, except that the resistance measurements made shall include not only the contact
resistance itself, but also the resistance of all connecting wires, solder joints, terminals, and so forth,
which form the associated circuitry of the set of contacts. The following details shall apply:
a. Method of connection The measuring apparatus shall be connected to the switch under
test, utilizing the normal means by which the switch will be connected in actual use, i.e.,
receptacles and connectors, terminal blocks, pigtail leads, and so forth. Provision shall be
made for testing each set of contacts and its associated circuitry when multicontact or
multipole switches are involved.
b. Test current and maximum test voltage The test current and test voltage may be any
values compatible with the test method employed, but shall not exceed the rated values of
c. Actuations prior to measurement Three mechanical actuations before measurement shall
be allowed.
d. Number of test actuations Three.
e. Number of measurements per actuation One.
f. Resistance measurements shall be made before and after endurance testing, as specified in
table II, and the resistance rise of each set of contacts and its associated circuitry shall not
exceed 100 milliohms. The final resistance shall not exceed 250 milliohms.
4.7.19 Endurance (see 3.23). Switches shall be tested for endurance in accordance with the
following. The media specified or an approved equivalent shall be used.
a. Operational cycling Switches shall be subjected to the total number of mechanical and
from 0.25 GPM or 20 percent below the minimum actuating or deactuating flow rates,
whichever is less, to the specified system flow rate plus or minus 10 percent. The flow rate
shall then be reduced to the initial flow rate. Unless otherwise specified, the flow rate
gradients shall be as equal as possible, and the holding times at minimum and maximum flow
rates shall be as equal as possible. The cycling rate shall not exceed 30 cycles per minute.
b. Measurements during endurance cycling Switch cycling shall be halted at the 10, 20, 30,
40, 50, 60, 70, 80, and 90 percent completion endurance stages. At each of these stages,
the switches shall be subjected to the tests for calibration, proof flow, differential pressure and
conducted at ambient environmental conditions, unless otherwise specified (see 3.1).
c. Measurements following endurance cycling Switches shall be tested for all requirements
specified for group A, in table III.
accordance with method 110 of MIL-STD-202. The following details shall apply
a. Test condition B.
b. Measurements Switches shall be within tolerances specified.
accordance with method 109 of MIL-STD-202. The following detail shall apply:
Mechanical and electrical load Switches shall be operated at their maximum rated dc
specified.
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