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.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13

MIL-PRF-28776F

4.8.15 Resistance to soldering heat (see 3.20). Relays shall be tested in accordance with method 210 of MIL-

STD-202. The following details and exceptions shall apply:

a. Depth of immersion in molten solder: Within .060 �.020 inch (1.52 �0.51 mm) of the relay base.

b. Test condition: B.

Measurements after test: Insulation resistance, contact resistance (or contact voltage drop), pickup, hold,

dropout, turn-on, and turn-off voltage, and coil current shall be measured as specified in 4.8.5, 4.8.7.1,

d. Examination after test: As specified in 4.8.9e.

4.8.16 Salt spray or salt atmosphere (corrosion) (see 3.21). Relays shall be tested as specified in 4.8.16.1 or,

when specified (see 3.1), in accordance with 4.8.16.2.

4.8.16.1 Salt spray, MIL-STD-202 (see 3.21). Unless otherwise specified, relays shall be tested in accordance

with method 101 of MIL-STD-202. The following details and exceptions shall apply:

Applicable salt solution: 5 percent.

Test condition: B.

Examination after test: Relays shall be examined for evidence of peeling, chipping, blistering of the finish,

and exposure of base metal due to corrosion that can adversely affect the operation or performance of the

relay.

4.8.16.2 Salt atmosphere (corrosion), MIL-STD-750-1 (when specified, see 3.1). Relays shall be tested in

accordance with method 1041 of MIL-STD-750-1. The following detail shall apply: Examination after test: As

specified in 4.8.16.1c.

4.8.17 Overload (applicable to high level relays only) (see 3.22). Relay contacts (both normally open and normally

closed) shall be subjected to the tests specified in 4.8.17.1 through 4.8.17.2, as applicable. For double-throw relays,

separate tests shall be performed for the normally open and the normally closed contacts. Relay coil energization

shall be nonsynchronous with the power supply for ac loads. The number of cycles shall be 100 for dc contact loads,

and 200 for ac contact loads ("on" and "off" times shall be approximately equal). The coil circuit shall be energized at

rated voltage. Overload current shall be twice the rated load current. The opening and closing of all contacts under

test shall be continuously monitored to detect switching of the contacts. The equipment shall be capable of

monitoring 40 percent minimum of the actual opened and closed time of each contact. The equipment shall

automatically cut off when a failure occurs, or shall record any failures. The relay case shall be connected to system-

ground through a normal-blow fuse rated at 5 percent of the test current or 100 mA, whichever is greater. After the

test, the fuse shall be tested for electrical continuity.

4.8.17.1 Resistive load. Suitable noninductive resistors shall be used. Cycling rate shall be 20 �2 cycles per

minute (cpm).

4.8.17.2 Inductive load. Cycling rate shall be 10 �1 cpm. Inductive load testing should be performed as

recommended by MIL-HDBK-338 and approved by the qualifying activity.