MIL-DTL-12211 Switch, PressureThis specification covers two types of automotive pressure switches \(see 6.1\). Type I switches operate when fluid pressures drop below predetermined values and type II switches operate when fluid pressures exceed predetermined values.

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MIL-DTL-12211G

3.3.1 Threaded parts. Screw threads of the form, number per inch, and class specified on the

applicable drawing or military standard shall be in accordance with FED-STD-H28 (see 4.7.2).

3.3.2 Rating. The switch shall be operated in nominal 24 volts (V) direct current (dc) electrical

systems, and shall operate a nominal 6 watt (3 candlepower) lamp, or loads as specified on applicable

MS standards or drawings (see 4.7.2).

3.4 Performance.

3.4.1 Calibration (see 4.7.3).

3.4.1.1 Type I switches. Type I switches shall close on decreasing pressure within the pressure range

specified on the applicable MS standard or drawing, and shall remain closed while the pressure is below

the lower value specified therein. Type I switches shall open on subsequently increasing pressure at not

less than the lower value and not more than 2 pounds per square inch (psi) above the upper value (see

3.4.1.2 Type II switches. Type II switches shall close on increasing pressure, within the actuation

range specified on the applicable MS standard or drawing and shall remain closed while the pressure is

above the upper value specified therein. Type II switches shall open on subsequently decreasing

pressure at not more than the upper value and not less than 2 psi below the lower value (see 4.7.3.2).

3.4.2 Terminal strength. Terminals shall withstand a force of 25 pounds without becoming deformed

more than .062 inch (1.57 mm) or evidencing damage to the switch body. The switch shall subsequently

meet the requirements of 3.4.1.1 or 3.4.1.2, as applicable (see 4.7.4).

3.4.3 Pressure overload. Switches shall withstand a pressure overload, as specified on the applicable

MS standard or drawing for 1 minute. After overloading, the change in switch opening or closing pressure

shall be not more than 8 percent. If no overload pressure is specified, pressure shall be 10 times

actuating and overload pressures shall conform to table I (see 4.7.5).

TABLE I. Pressures for type I, class 2 of MS90530.

Actuating

Overload

pressure

pressure (psi)

4- 8

9 - 13

15 - 19

23 - 27

28 - 32

100

44 - 50

100

60 - 65

150

3.4.4 High voltage. Switches shall withstand 220 V root mean square (rms) at 60 hertz (Hz) for 1

minute without evidence of sparking, arcing, burning, smoking, charring, or other insulation damage (see

3.5 Environmental conditions.

3.5.1 Corrosion resistance. Switches shall withstand 200 hours of salt spray with no degradation in

performance (see 4.8.1).