MIL-PRF-28776F
TABLE VI. Group B inspection.
Inspection
Requirement
Test method
paragraph
paragraph
Life 1/
Dielectric withstanding voltage 2/
Insulation resistance 2/
Electrical characteristics 2/, 3/
Visual inspection (external)
1/
Sample units shall be tested in a predetermined sequence as defined by the
manufacturer and approved by the qualifying activity. All loads specified in the
applicable specification sheet shall be represented. All loads need not be represented
in a 6-month maintenance period but shall be represented within two 6-month
maintenance periods.
2/
Coil current may be performed prior to dielectric withstanding voltage and insulation
resistance. The 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.
3/
The coil resistance of hybrid relays is not directly measurable at the relay terminals
due to the resistance of the drivers.
4.7.3.2 Group C inspection. Group C inspection shall consist of the tests in the order specified in table VII. Group
C inspection shall be made on sample units selected from inspection lots which have passed the group A inspection.
4.7.3.2.1 Sampling plan. Three sample units shall be taken from production every month for C1, two samples for
C2 every 6 months, two samples for C3 every 6 months, two samples for C4 every 6 months, two samples for C5
every 12 months, and two samples for C6 every 36 months.
4.7.3.2.1.1 Similarity. For purposes of complying with group C requalification, relays, of similar construction and
4.7.3.2.2 Failures. No failures shall be permitted except for intermediate current in C1. 2/
4.7.3.2.3 Disposition of sample units. Sample units which have been subjected to group C inspection shall not be
delivered on the contract or purchase order.
4.7.3.3 Noncompliance. During group B and C inspections, when a failure exceeds the allowable number of
failures, the manufacturer shall notify the qualifying activity and the cognizant inspection activity of such failure within
5 working days. The manufacturer shall prepare to take corrective action on the materials or processes, or both, as
warranted, and on all units of product which can be corrected and which were manufactured under essentially the
same materials and processes, and which are considered subject to the same failure. Acceptance and shipment of
the product shall be discontinued until corrective action, acceptable to the qualifying activity has been taken. After
the corrective action has been taken, group B and C inspections shall be repeated on additional sample units (all
tests, or the tests which the original sample failed, at the option of the qualifying activity). Group A inspection may be
reinstituted; however, final acceptance and shipment shall be withheld until the group B or C inspection has shown
that the corrective action was successful. In the event of failure after reinspection, information concerning the failure
shall be furnished to the qualifying activity and the cognizant inspection activity within 5 working days.
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2/ One intermediate current failure per 6-month retention period shall be permitted per FR groupings of similar relay
types as approved by the qualifying activity.
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