MIL-DTL-24317B
4.8.21 Electrical endurance (see 3.24).
4.8.21.1 Conditions.
(a) Unless otherwise specified (see 3.1), test loads shall be arranged so that an independent load
shall be provided for each pole, and the life cycle for each electrical load shall be 25,000 cycles.
(b) Switches shall be continuously monitored and recorded to determine whether any contact has
failed to open or close its individual circuit in the proper sequence. The monitoring circuit shall
not shunt inductive components of inductive loads or switch contacts.
(c) The duty cycle shall be approximately 50 percent on and 50 percent off for resistive and inductive
loads. The duty cycle shall be approximately 30 percent on and 70 percent off for lamp loads.
(d) The cycling rate shall be 10 to 12 cycles per minute.
(e) When testing switch styles having normally open and normally closed contact arrangement,
samples shall be equally divided between the two arrangements. All samples shall be tested in
their normal positions.
(f) In any of the specified load tests, each conductor shall be of an applicable size for single use in
free air as listed in SAE-AS50881. If the rating of the switch under test does not coincide with a
wire size, the next larger diameter wire shall be used.
(g) One side of the power supply, one side of the test load, the switch mounting plate, metal housing
(if applicable), and the actuating member, if metal, shall be connected to a common ground.
4.8.21.2 Loads. Voltage, current, frequency, and altitude, shall be as specified (see 3.1), however,
altitude electrical tests shall be conducted at room ambient condition only. Unless otherwise specified,
the life cycle for each electrical load shall be 25,000 cycles. The loads are as follows:
(a) Resistive load, dc. Only noninductive resistive components shall be used.
(b) Inductive load, dc.
(1) Method I. Inductive dc loads shall use inductors, so adjusted that the time constant L/R (time
required for current to reach 63.2 percent of its steady-state value) shall be not less than
0.025 second.
(c) Lamp load, dc. Lamp loads, dc, shall be tungsten lamps which provide the rated, steady-state
lamp current. Only tungsten lamps having a nominal wattage of 25 to 50 watts, of the voltage
specified, shall be used to make up the load.
(d) Resistive load, ac. Only noninductive resistive components shall be used.
(e) Inductive load, ac. Inductive ac load test circuits shall consist of inductive and resistive load
elements connected in series. The circuit parameters shall be rated inductive load current at 0.7
± 0.05 lagging power factor at 115 volts.
(f) Lamp load, ac. Similar to (c) above, except that the rated ac voltage shall be used. Only
tungsten lamps having a nominal wattage not to exceed 200 watts, at the voltage specified, shall
be used to make up the load.
5. PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the
contract or order (see 6.2). When packaging of materiel is to be performed by DoD or in-house contractor
personnel, these personnel need to contact the responsible packaging activity to ascertain packaging
requirements. Packaging requirements are maintained by the Inventory Control Point's packaging
activities within the Military Service or Defense Agency, or within the military service's system commands.
Packaging data retrieval is available from the managing Military Department's or Defense Agency's
automated packaging files, CD-ROM products, or by contacting the responsible packaging activity.
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