MIL-PRF-28776 Relays, Hybrid, Established Reliability, General Specification ForThis specification establishes the general requirements for relays that use a combination of solid state circuit input elements functioning with an electro-mechanical relay that performs the switching functions associated with control system applications \(see 6.1\). These relays are designed to operate in low and medium power switching circuits with contact ratings up to 1 ampere alternating current \(ac\) or direct current \(dc\). The failure rate level is established at a confidence level of 90 percent for qualification and 60 percent for maintenance of qualification based on 100,000 cycles at +125┬░C under rated load conditions specified herein. Excludes time delay relays. CAUTION: The use of any coil voltage less than the rated coil voltage will compromise the operation of the relay. CAUTION: Pick-up, hold, and dropout voltages are for test purposes only and are not to be used as design criteria. For additional application and caution information, see 6.1.

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MIL-PRF-28776F

4.8.4.1 Relays sealed with or without a tracer gas. Relays shall be tested for fine leak and gross leak using one of

the fine leak procedures and one of the gross leak procedures in the following table. Fine leak shall be performed

prior to gross leak, unless MIL-STD-883 (method 1014) Test Condition B2/B1 is used. The standard leak rate (L value

in Eq. (1) of MIL-STD-883 Method 1014) shall be 1 X 10 -6 atm cm3/s of air.

Fine Leak

MIL-STD-883 (method 1014) � Test Condition B1

MIL-STD-883 (method 1014) � Test Condition A2

Gross Leak

MIL-STD-883 (method 1014) � Test Condition B2

MIL-STD-202 (method 112) � Test Condition D

MIL-STD-883 (method 1014) � Test Condition C

Fine Leak and Gross Leak Combination

MIL-STD-883 (method 1014) � Test Condition B2/B1

When using the radioisotope tests, it is recommended practice to use B2 first to remove gross leakers prior to the fine leak

test B1, which minimizes the Kr85 entrapped in rejected devices.

4.8.5 Insulation resistance (see 3.10). Relays shall be tested in accordance with method 302 of MIL-STD-202 with

the relay in the energized and de-energized positions. The hybrid device should be protected during testing in the

deenergized position. Unless other specified (see 3.1), the following details shall apply:

Test conditions: A (for relays with coil and contact ratings both below 60 volts) and B (for all other relays).

Points of measurement: As specified in points of application in table VIII.

Attributes data is acceptable.

4.8.6 Dielectric withstanding voltage (see 3.11). Relays shall be tested as specified in 4.8.6.1 and in accordance

with 4.8.6.2. Testing in accordance with 4.8.6.2 is not applicable to groups A, B, C1, or C5. The hybrid device should

be protected during testing in the deenergized position.

4.8.6.1 At atmospheric pressure. Relays shall be tested in accordance with method 301 of MIL-STD-202. Unless

otherwise specified (see 3.1), the following details shall apply:

Points of application and magnitude of test voltage: As shown in table VIII.

Maximum leakage current: 100 A. For group A, leakage current measuring device shall be capable of

measuring the leakage current to an accuracy of at least 10 percent.

Duration of application: 60 seconds minimum for qualification and groups B and C tests; 5 (60 Hz) cycles

minimum for group A tests on test equipment which has an adequate response time to measure the

leakage current and is approved by the qualifying activity. For group A tests on other than automatic test

equipment (i.e., bench setup), the application time shall be 5 seconds minimum.

Attributes data is acceptable.