Numerous tests of aircraft electronics and other electrically powered devices on board an aircraft are intended to show whether the devices can withstand overvoltage and undervoltage conditions, power failures and voltage transients. MIL-HDBK-704-7 and MIL-HDBK-704-8 describe the test methods and procedures for devices designed to operate at 270 VDC and 28 VDC respectively.
MIL-HDBK-704-7 270 VDC current interruption
MIL-HDBK-704-7 describes the “Guidance for Test Procedures for Demonstration of Utilization Equipment Compliance to Aircraft Electrical Power Characteristics, 270 VDC”. One test required therein is the so-called Power Interrupt Test, according to the HDC201 method. This test procedure can be used to verify whether the 270 V DC utilization equipment functions reliably and maintains its specified performance even during power interruptions. To perform this test, the appropriate input voltage (nominal, low or high) is first applied to the device. The device is then verified to ensure that it meets the power specifications. The power supply is then switched off for 50 ms and then restored. Finally, the device is tested again to ensure that it meets the power specifications. EA’s bidirectional DC power supplies with autoranging function meet these demanding requirements. The DC power supplies, which deliver up to 30 kW, have very low EMC emissions and feature galvanically isolated USB, Ethernet/LAN or GPIB interfaces.