MIL-STD-704 Aircraft Electrical Power Characteristics is a United States Military Standard that defines a standardized power interface between a military aircraft and its equipment and carriage stores, covering such topics as voltage, frequency, phase, power factor, ripple, maximum current, electrical noise and abnormal conditions (overvoltage and undervoltage), for both AC and DC systems.
References
MIL-STD-704 Wikipedia(Text) CC BY-SA