MIL-STD-704 Aircraft Electric Power CharacteristicsThis standard establishes the requirements and characteristics of aircraft electric power provided at the input terminals of electric utilization equipment. MIL-HDBK-704-1 through-8 defines test methods and procedures for determining airborne utilization equipment compliance with the electric power characteristics requirements defined herein. Electromagnetic interference and voltage spikes are not covered by this standard.

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Steady state characteristics

Limits

Steady state voltage

Voltage unbalance Voltage modulation Voltage phase difference Distortion factor Distortion spectrum

Crest factor

DC component

Steady state frequency

Frequency modulation

105.0 to 125.0 Volts, RMS

3.0 Volts, RMS maximum

2.5 Volts, RMS maximum

116° to 124°

0.05 maximum

Figure 12

1.31 to 1.51

+0.10 to - 0.10 Volts

59.5 to 60.5 Hz

0.5 Hz

Transient characteristics

Limits

Peak voltage

Voltage transient

Frequency transient

±271.8 Volts

Figure 8

Figure 10

Steady state characteristics

Limits

28 Volt DC system

270 Volt DC system

Steady state voltage

Distortion factor Distortion spectrum Ripple amplitude

22.0 to 29.0 Volts

0.035 maximum

Figure 15

1.5 Volts maximum

250.0 to 280.0 Volts

0.015 maximum

Figure 18

6.0 Volts maximum

Limits

Transient characteristics

28 Volts

DC system

270 Volts

DC system

Voltage transient

Figure 13

Figure 16