MIL-STD-1275 Characteristics Of 28 Volt Dc Input Power To Utilization Equipment In Military VehiclesThis standard defines the operating voltage limits and transient voltage characteristics of the 28 VDC electrical power at the input power terminals to the utilization equipment connected to the electrical power distribution system on military ground vehicle platforms.

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MIL-STD-1275E

5.2.5    Measurement reference point.

The measurement reference point for EUTs shall be the power input terminals of the EUT.

EUTs having multiple power input terminals shall be individually and simultaneously monitored during the test(s).  All transient voltage waveforms applied to EUTs shall be verified open circuit; i.e., no load.

5.2.6    Power return.

The test setup shall use a power return for the EUT as required by the applicable performance specification.

If a power return is not specified, the EUT power return conductor shall be equivalent to the

EUT power source conductor.

In cases where the EUT uses the vehicle structure as the power return, a ground plane in accordance with (IAW) MIL-STD-461 shall be used to simulate the vehicle's metal structure as the return current path.  The negative (-) terminal of the EUT as well as the negative (-) terminal of the power source shall be bonded to the ground plane.

5.2.7    Loads.

Loads representative of the actual installation on vehicle shall be used to test the EUT if the EUT

is not a standalone device.

5.2.8    Power supply.

Power supplies shall maintain ±1% of specified voltage during testing, as measured at their output.

5.3     Voltage compatibility verification method.

5.3.1    Steady state operation.

5.3.1.1 Operational voltage range.

The EUT shall be tested to operate as specified while subjected to the voltages/durations at both the lower and higher limits of the voltage envelope shown in Figure 8.  Any deviation from normal operation shall be recognized as a failure of the EUT.

5.3.1.2 Voltage ripple.

Unless otherwise specified in the applicable performance specification, the test method and limits for voltage ripple specified in MIL-STD-461 CS101 shall be used at nominal voltages of

23 VDC and 30 VDC with the same values used at 150 kHz extended to 250 kHz, as shown in

Figures CS101-1 and CS101-2.

Verify the EUT operates as specified while subjected to the ripple.  Any deviation from normal operation shall be recognized as a failure of the EUT.

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