MIL-DTL-28827 Switches, Thermostatic, \(Volatile Liquid\), Hermetically Sealed, General Specification ForThis specification covers the general requirements for hermetically sealed volatile liquid thermostatic switches intended primarily for use in equipment requiring rapid temperature response. The operating temperatures and operating temperature ranges of switches covered by this specification are as specified \(see 3.1 and 6.1.2\).

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MIL-DTL-28827C

3.16 Contact resistance. Unless otherwise specified (see 3.1 and 6.1.2), when measured as specified

in 4.7.12, the initial contact resistance shall not exceed 100 milliohms: following the endurance test,

contact resistance shall not exceed 250 milliohms.

3.17 Connector torque (applicable to switches with electrical connectors). When switches are tested

as specified in 4.7.13, there shall be no loosening, rotation, distortion, short circuit or other damage. The

operating points shall be within the tolerances specified (see 3.1).

3.18 Terminal strength (when applicable). When switches are tested as specified in 4.7.14, there shall

be no breakage, loosening, or rotating of terminals, and no damage to the switch body.

3.19 Short circuit (when specified, see 3.1). When switches are tested as specified in 4.7.15, there

shall be no welding or sticking of contacts, or other damage. Switches shall be mechanically and

electrically operative at the end of the test.

3.20 Vibration. Unless otherwise specified (see 3.1 and 6.1.2), when switches are tested as specified

in 4.7.16, closing of open contacts and opening of closed contacts shall not exceed 250 microseconds.

The operating points shall be within the tolerance specified (see 3.1).

3.21 Shock. Unless otherwise specified (see 3.1 and 6.1.2), when switches are tested as specified in

4.7.17, there shall be no change in operation, or evidence of broken, deformed, displaced, or loose parts.

3.21.1 Method I (shock, specified pulse) (see 3.1 and 6.1.2). When switches are tested as specified in

4.7.17.1, closing of open contacts and opening of closed contacts shall not exceed 250 microseconds,

unless otherwise specified (see 3.1 and 6.1.2).

3.21.2 Method II (high-impact shock) (see 3.1 and 6.1.2). When switches are tested as specified in

4.7.17.2, closing of open contacts and opening of closed contacts shall not exceed 5 milliseconds, unless

otherwise specified (see 3.1 and 6.1.2).

3.22 Overload cycling. When switches are tested as specified in 4.7.18, there shall be no mechanical

or electrical failure.

3.23 Endurance. When switches are tested as specified in 4.7.19, each contact shall open and close

its circuit in proper sequence during each cycle. During and after the cycling, there shall be no evidence

of malfunction, damage, or leakage, and the operating points shall be within the tolerances specified (see

3.24 Salt spray (corrosion). When switches are tested as specified in 4.7.20, switches shall show no

evidence of destructive corrosion. After the test, any mounting hardware (if applicable) shall be readily

removable. NOTE: Destructive corrosion shall be construed as being any type of corrosion which in any

way interferes with the mechanical or electrical performance, or in the case of plated metals, corrosion

which has passed through the plating and attacked the base metal

3.25 Marking. Switches shall be marked in accordance with MIL-STD-1285 with the military part

number or the manufacturer's part number when specified (see 6.1.2), date code, and the manufacturer's

trademark or code symbol.

3.26 Workmanship. Switches shall be proposed in such a manner as to be uniform in quality and shall

be free from cracked or displaced parts, sharp edges, burrs, and other defects which will affect life,

serviceability, or appearance.