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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

TABLE V. Group A inspection. 1/

Inspection

Requirement

Test

Inspection

paragraph

method

requirements

paragraph

Vibration (sinusoidal) 2/

3.15

4.8.10.1

100 percent

Screening, internal moisture 3/

3.7

4.8.2.1

see 3/

Screening, run-on

100 percent

3.7

4.8.2.2

100 percent

Dielectric withstanding voltage 4/

3.11

4.8.6

Insulation resistance 4/

3.10

4.8.5

Electrical characteristics 4/

2 samples

Solderability

100 percent

3.1, 3.28,

4.8.1

Visual and mechanical inspection

(external) 5/ 6/

3.29, 3.32

Seal

3.9

4.8.4

1/ Tests shall be performed in the order shown.

2/ For FR level L relays, the vibration (sinusoidal) test shall be performed on 13 relays per lot with no

failures allowed. In the event of a failure, the lot shall be 100 percent inspected. For lots with fewer

than 13 relays, the lot shall be 100 percent inspected.

3/ The internal moisture test shall be performed on 13 relays per lot with no failures allowed. In the

event of a failure, the lot shall be 100 percent inspected. For lots with fewer than 13 relays, the lot

shall be 100 percent inspected.

4/ Coil current may be done prior to dielectric withstanding voltage and insulation resistance. Testing

sequence is optional for insulation resistance and dielectric withstanding voltage prior to the

electrical characteristics. Turn-on voltage (or current), see 3.1, and turn-off voltage may be done

after coil transient suppression voltage.

5/ Minor defects, such as marking may be reworked. A two piece sample of each lot shall be mechanically

inspected and visually inspected for cracked glass. If cracks exceeding the allowable limits are found, the

entire lot shall be inspected to the criteria of 3.29.

6/ A two piece sample of each relay style be inspected in accordance with 6.3.1, except as limited by the

housing style or external attachments.