MIL-PRF-24236 Switches, Thermostatic, \(Metallic And Bimetallic\), General Specification ForThis specification covers the general requirements for metallic-element actuated, thermostatic switches intended primarily for use in electrical and electronic equipment, in alternating current \(ac\) and direct current \(dc\) applications, where temperature protection, overheat detection, or accurate temperature control is required. The operating temperatures and operating temperature ranges of switches are covered by this specification \(see 3.1 and 6.2.2\).

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MIL-PRF-24236D

4. VERIFICATION.

4.1 Test equipment and inspection facilities. Test and measuring equipment and inspection facilities of sufficient

accuracy, quality and quantity to permit performance of the required inspection shall be established and maintained

by the supplier. The establishment and maintenance of a calibration system to control the accuracy of the measuring

and test equipment shall be in accordance with ANSI/NCSL Z540-1, ISO-10012-1, or equivalent system as approved

by the qualifying activity.

4.2 Classification of inspection. The inspections specified herein are classified as follows:

a. Qualification inspection (see 4.4).

b. Conformance inspection (see 4.5).

4.3 Inspection conditions. Unless otherwise specified herein, all inspections shall be performed in accordance with

the test conditions specified in the "GENERAL REQUIREMENTS" of MIL-STD-202 with the following exception:

Relative humidity shall be 20 to 75 percent.

4.4 Qualification inspection. Qualification inspection shall be performed at a laboratory acceptable to the

Government (see 6.3) on sample units produced with equipment and procedures normally used in production.

4.4.1 Sample size. The number of switches to be subjected to qualification inspection shall be as specified (see

4.4.2 Inspection routine. The sample shall be subjected to the inspections specified in table I in the order shown.

All sample units shall be subjected to the inspections of group I in the order shown. The sample shall then be divided

as specified in table I for groups II to VI inclusive, and subjected to the inspection for their particular group.

4.4.3 Failures. One or more failures shall be cause for refusal to grant qualification approval.

4.4.4 Extent of qualification.

4.4.4.1 Single submission. Qualification shall be restricted to the switch submitted.

4.4.4.2 Group submission. If samples satisfactorily pass the qualification inspection, other switches from the same

manufacturer that have the same operation, or reverse operation, design, construction, switching characteristics,

class, and physical dimensions will be considered qualified by the Government without further qualification inspection.

4.4.4.3 Qualification by classes. Qualified switches of class 5 shall provide qualification for classes 6, 4, 3, 21/,

and 1. Class 3 shall provide qualification for classes 2 1/ and 1. Qualification will be granted for switches having

tolerances and differentials greater than those qualified.

1/ For class 2 qualification, two additional sample units shall be subjected to calibration and high-impact shock tests