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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MIL-STD-704F CONTENTS

PARAGRAPH                                                                                                                         PAGE

6.         NOTES       ....................................................................................................................... 10

6.1                   Intended use  ......................................................................................................... 10

6.2                   Considerations ...................................................................................................... 10

6.3                   Supersession data ................................................................................................. 10

6.4                   International standardization implementation ...................................................... 10

6.5                   Changes from previous issue  ............................................................................... 10

6.6                   Application of this standard in utilization equipment specifications ................... 10

6.7                   Pulsed load design issues ..................................................................................... 11

6.8                   Non-linear loads and effects  ................................................................................ 11

6.9                   Precedence  ........................................................................................................... 11

6.10                 Guidance and lessons learned  .............................................................................. 11

6.10.1              Compatibility and testing ..................................................................................... 11

6.10.2              Compatibility and installation .............................................................................. 12

6.11                 Subject term (keyword) listing ............................................................................. 12

TABLES

I                       AC normal operation characteristics - 400 Hertz (see 5.2.3) ............................... 13

II                     AC normal operation characteristics - variable frequency (see 5.2.3) ................. 13

III                    AC normal operation characteristics - 60 Hertz (see 5.2.3) ................................. 14

IV                    DC normal operation characteristics (see 5.3.2.1, 5.3.4.1) .................................. 14

FIGURES

1                      Load unbalance limits for three phase utilization equipment  .............................. 15

2                      Phasor diagram showing required phase sequence relationship .......................... 16

3                      Envelope of normal 400 Hz and variable frequency AC voltage transient  ......... 17

4                      Limits for 400 Hz and variable frequency AC overvoltage and undervoltage  .... 18

5                      Envelope of normal 400 Hz AC frequency transient ........................................... 19

6                      Limits for 400 Hz AC overfrequency or underfrequency .................................... 20

7                      Maximum distortion spectrum of 400 Hz and variable frequency AC voltage ... 21

8                      Envelope of normal 60 Hz voltage transient ........................................................ 22

9                      Limits for 60 Hz AC overvoltage and undervoltage ............................................ 23

10                    Envelope of normal 60 Hz AC frequency transient ............................................. 24

11                    Limits for 60 Hz AC overfrequency and underfrequency  ................................... 25

12                    Maximum distortion spectrum of 60 Hz AC voltage ........................................... 26

13                    Envelope of normal voltage transients for 28 volts DC system ........................... 27

14                    Limits for overvoltage and undervoltage for 28 volts DC system ....................... 28

15                    Maximum distortion spectrum for 28 volts DC system ....................................... 29

16                    Envelope of normal voltage transient for 270 volts DC system  .......................... 30

17                    Limits for DC overvoltage and undervoltage for 270 volts DC system  .............. 31

18                    Maximum distortion spectrum for 270 volts DC system. .................................... 32

CONCLUDING MATERIAL  ......................................................................................... 33

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