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MIL-PRF-22710 Switches, Code Indicating Wheel \(Printed Circuit\), Thumbwheel And Push-Button, General Specification ForThis specification covers the general requirements for illuminated and non-illuminated, thumbwheel \(see 6.4.1\), and push-button, printed circuit rotary switches having unsealed and sealed modules and the associated hardware. These switches are designed for low power alternating current \(ac\) and direct current \(dc\) switching applications for use in electronic and communication equipment. Procurement of switches and mounting hardware will require additional data, giving detailed electrical and mechanical requirements, tolerances, and applicable additions and exceptions to the general requirements and tests specified herein \(see 6.2\).

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MIL-PRF-22710H

TABLE X. Group C inspection.

Requirement

Method

Inspection

paragraph

Subgroup I (4 sample units)

Thermal shock

Vibration

Shock

Rotational torque or operating force (as applicable)

3.19

4.5.16

Moisture resistance (includes insulation resistance)

Contact resistance

Seal (when applicable)

Dielectric withstanding voltage

3.18

4.5.15

Subgroup II (4 sample units)

Terminal strength (when applicable)

3.11

4.5.8

Strength of mounting bushing (when applicable)

Rotational torque or operating force (as applicable)

3.15

4.5.12

Insulation resistance

Contact resistance

Circuit configuration

Indicator ring

Seal (when applicable)

Dielectric withstanding voltage

3.18

4.5.15

Subgroup III (4 sample units)

Sand and dust (when applicable)

Explosion (when applicable)

3.24

4.5.21

Salt spray (corrosion)

Contact resistance

Rotational torque or operating force (as applicable)

3.17

4.5.14

Seal (when applicable)

Dielectric withstanding voltage 1/

3.18

4.5.15

Subgroup IV (4 sample units, divided equally)

Life (rotational), at rated ac load (resistive)

3.25

4.5.22

Life, low level switching

3.26

4.5.23

Subgroup V

4.5.24

Solderablitiy (2 sample units only)

3.27

1/ Only when seal is applicable.

4.5.4.3 Color. The chromaticity of the light projected shall be determined by spectrographic or other equivalent

visual means and shall meet the requirements of 3.4.7.6.

4.5.5 Rotational torque or operating force (as applicable, see 3.1 and 6.1) (see 3.8). Switches shall be tested as

specified in 4.5.5.1 or 4.5.5.2, as applicable. The following conditions and procedures shall apply:

a. Mounting: By their normal mounting means, unless otherwise specified (see 3.1 and 6.2.2).

b. Room temperature: The values of torque or force required to rotate the switch through all positions in both

directions shall be determined. All values shall be recorded and then the average value shall be recorded.

All readings shall be observed to determine whether they are within the limits as specified. On concentric

shaft switches, the rotational torque (see 3.1) shall be measured while rotating the inner shaft when a dummy

knob (see NASM 91528) with two No. 8 (.164)-32 UNC-2A screws, 90 degrees apart, tightened to 15 pound-

inches minimum, is placed on the outer shaft.

c. Minimum temperature: Switches shall be exposed to a temperature of -65�C �2�C for a period of 4 hours.

The minimum and maximum values of torque or force required to rotate the switch, through all positions in

both directions, shall be determined while the switch is maintained at -65�C �2�C. The average torque level

shall be not greater than 125 percent of the torque required at room temperature.

4.5.5.1 Rotational torque (applicable to external drive shaft switches, see 3.8.1). Inline switches shall be tested by

applying the specified torque (see 3.1 and 6.2.2) to the shaft of the switch.