AFGS�87219B APPENDIX A
REQUIREMENT RATIONALE (A.3.2.8)
Appropriate means of control and protection are necessary for the safe and effective operation of the EPS. Factors to be considered include crew instrumentation and controls, failure modes and effects, automatic control and protection, reliability, vulnerability, and safety. AFSC Design Handbooks DH 1-6 and DH 2-3 and JSSG 2009 have previously stated subsystem requirements.
REQUIREMENT GUIDANCE (A.3.2.8)
a. Means of controlling the EPS should be provided such that mission and safety requirements are met without unnecessarily burdening the crew. On the other hand, the crew should be involved in non-routine situations in which crew action can improve mission effectiveness or control abnormal or hazardous conditions. Interface with crew station/human factors engineers when establishing instrument and manual control requirements.
b. Coordinate warning/caution/advisory requirements related to this specification with crew station/human factors engineers. Refer to JSSG-2010 and MIL-STD-1800 for further guidance on the location and actuation of the instruments and manual controls, and further guidance on indicator system requirements. Older systems may refereance the canceled, MIL-STD-1776 and MIL-STD-1800. They should only be used for information.
c. The multiplexing of control signals for the EPS and for the monitoring and control of individual load circuits is a possible option to reduce the amount of wiring required. MIL-STD-1553 gives requirements for multiplexed data buses.
d. All component failure modes should be identified and means to accommodate them provided. No segment of the EPS from prime mover output to the load equipment terminals should be unprotected.
e. The advantages of redundant components are realized only if the components are sufficiently isolated electrically and physically so that multiple failures are improbable. Furthermore, if there is no way to detect the failure of a redundant component, the value of redundancy is lost.
f. Requirements for electrical power generation system control and protection are provided by MIL-E-85583.
g. Solid state power controllers should be used whenever possible. They provide faster switching times, which are effective at preventing arc-tracking.
REQUIREMENT LESSONS LEARNED (A.3.2.8)
a. One electrical power generation subsystem was designed to parallel the main generators through bus tie contractors (BTC). As originally designed, the BTCs would
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