MIL-PRF-28750F
4.3.1 Power supply. Unless otherwise specified herein, the power supply shall have no more than 5 percent
regulation at 110 percent of the specified test current. A dc power supply shall have no more than 5 percent ripple
voltage. An ac power supply shall be within 1 percent of the specified frequency and shall be sinusoidal with a form
factor between 0.95 and 1.25.
4.3.1.1 Grounding. Unless otherwise specified (see 3.1), the negative side of the dc power supply shall be
grounded; one side of single-phase ac power supply shall be grounded; or the neutral of 3-phase ac power supply
shall be grounded, as applicable.
4.3.2 Load conditions during tests. The input of the SSR being tested shall be connected to the grounded side of
its power supply; each load of the SSR being tested shall be connected to the grounded side of its power supply; and
each output shall be connected to an individual load. Separate power supplies shall be used for the input to the SSR
and the individual load being tested.
4.4 Qualification inspection. Qualification inspection shall be performed at a laboratory acceptable to the
Government (see 6.3) on sample SSR's produced with equipment and procedures normally used in production.
Qualifications of the "W" screening level PIN is predicated upon qualification of the "Y" screening level PIN. Upon
request of the manufacturer, qualification to the "W" screening level PIN's will be granted for the envelope of products
successfully qualified to the "Y" screening level PIN's. The products involved shall be of the same design,
manufactured using the same facilities, processes, and materials as the product originally submitted for and qualified
under the "Y" screening level.
4.4.1 Sample size. The number of SSR's to be subjected to qualification inspection shall be 12. In addition,
submit one unsealed sample to the qualifying activity as part of the qualification procedure. The sample SSR's shall
be taken at random from a production run and shall be produced with equipment and procedures normally used in
production, and which have been subjected to and passed the requirements of group A inspection (see 4.6.1.2).
Qualification shall not be granted if group A inspection requirements are not complied with.
4.4.2 Inspection routine. Qualification samples shall be subjected to the tests as specified in table I, in the order
shown, as applicable for each SSR. All sample units shall be subjected to group Q1. The sample units shall then be
divided into three groups of four and shall then be subjected to group Q2, group Q3, and group Q4.
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