MIL-HDBK-1004/5
Section 3: DESIGN REQUIREMENTS
3.1
Design Procedures. Preliminary design procedures for 400-Hz systems
are the same as those for 60-Hz systems (loads, distances, etc.) so that the
system design will meet project requirements.
3.1.1
Data Gathering. Determine the following data regardless of whether
an entirely new installation is being designed or an existing facility is
being changed or upgraded. While a new facility allows more leeway in the
design approach, the available load data ordinarily will not be as precise.
Gather or design concurrently with the 400-Hz system the following data:
a) Facility electrical site plans with locations of all aircraft
service points.
b) Facility electrical building plans having 400-Hz loads or used
to house 400-Hz equipment.
c) Determination of all 400-Hz load specifications including both
requirements for new loads and replacement or reuse of any existing 400-Hz
low-voltage conversion distribution system.
d)
Data on the proposed or installed 60-Hz primary distribution
system.
3.1.2
System Layout. From the above data, develop a system layout which
locates possible distribution line choices and pinpoints load connection
points.
3.1.3
Equipment Layout. After the development of the system layout, make
equipment locations based on the design aspects delineated in the following
paragraphs.
3.1.4
Design Aspects. The 400-Hz system consists of the following major
elements:
a)
The central power plant.
b)
The medium-voltage distribution system.
c)
The low-voltage utilization system.
The following considerations apply to the entire 400-Hz system design.
Protective Device Operation. Always consider the thermal and
3.1.4.1
magnetic characteristics for 400-Hz circuit protective devices. Operation at
400 Hz causes more heat rise in current-carrying parts than does operation at
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