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

4.8.9 Shock (specified pulse) (see 3.14). Unless otherwise specified (see 3.1), relays shall be tested in accordance

with method 213 of MIL-STD-202. The following details and exceptions shall apply:

Mounting method: For relays having flanges or studs, mounting shall be by the flanges or studs; and for

relays without flanges, mounting shall be by plugging into sockets, or other suitable means approved by the

qualifying activity.

Test condition: A, B, or C, as applicable (see 3.1).

Electrical-load conditions: In each direction of shock, the coil shall be deenergized during two shocks and

energized with rated voltage during one shock.

Measurements during shock: Contacts shall be monitored with an adequate test circuit as approved by the

qualifying activity. The test circuit shall verify that no opening of closed contacts in excess of 10 �s and no

false closure or bridging of open contacts occurs in excess of 1 �s. The contact load shall be 10 mA

maximum at 6 V dc maximum (dc or peak ac).

Examination after test: Relays shall be inspected for evidence of structural failure or other damage which

might impair the operation of the relay.

4.8.10 Vibration (see 3.15).

4.8.10.1 Vibration (sinusoidal). Unless otherwise specified (see 3.1), relays shall be tested in accordance with

method 204 of MIL-STD-202. The following details and exceptions shall apply:

Method of mounting: As specified in 4.8.9a.

Electrical-load conditions: For qualification and group C inspections, relays shall be tested with the coil

energized for 2 hours at rated voltage and with the coil de-energized for 2 hours, in each of the three

mutually perpendicular (x, y, and z) directions. Contacts shall be loaded as specified in 4.8.10.1d.

Test condition: D, except vibration level is the lesser of .195 inch (4.95 mm) double amplitude of 30 G, and

frequency range is 10 to 3,000 Hz.

Tests during vibration: As specified in 4.8.9d.

Unless otherwise specified (see 3.1), for group A testing, only one cycle shall be performed over the

frequency range of 100 Hz to 3,000 Hz. The relay shall be vibrated in the direction of contact motion. At

the option of the manufacturer, the relay production lot may be divided in three equal groups and each

group shall be tested in one of three mutually perpendicular axis (X, Y, and Z). When relays are tested as

specified in the optional procedure, a failure of any relay in any axis shall require 100 percent inspection of

all relays in the production lot in each axis. For all contact forms except contact form "A", the cycle shall

consist of 3 minutes up with the coil energized with rated voltage and 3 minutes down with coil de-

energized. The cycle for form contact "A" shall consist of 3 minutes up with the coil de-energized and 3

minutes down with the coil energized.

Examination after test: Prior to removal from test fixture and without disturbing the relay, apply maximum

over the temperature range pick-up voltage value and turn-on voltage (see 3.1) to the relay, and then verify

that relay contacts transfer. Remove coil voltage and turn-on voltage, and then verify that relay contacts

transfer. Failure of relay contacts to transfer shall be cause for rejection. After removal from test fixture,

the relays shall then be inspected for evidence of structural failure or other damage which might impair the

operation of the relay.