關于軸發是不是主電源的組成部分， SOLAS 有個解釋的。如下：Generators and generator systems, having the ship's main propulsion machinery as their prime mover, may be accepted as part of the ship's main source of electrical power, provided:
1 They should be capable of operating under all weather conditions during sailing and during manoeuvring, also when the ship is stopped, within the specified limits for the voltage variation in IEC 60092-301 and the frequency variation in IACS UR E5.
2 Their rated capacity is safeguarded during all operations given under 1, and is such that in the event of any other one of the generators failing, the services given under regulation II-1/41.1.2 (Interpretation 3) can be maintained.
3 The short circuit current of the generator/generator system is sufficient to trip the generator/generator system circuit-breaker taking into account the selectivity of the protective devices for the distribution system.
Protection should be arranged in order to safeguard the generator/generator system in case of a short circuit in the main bus bar. The generator/generator system should be suitable for further use after fault clearance.
4 Standby sets are started in compliance with paragraph 2.2 of SOLAS chapter II-1, regulation II-1/41.5 (Interpretation 5).
同時參照 UR E5。 如果，不是組成主電源和應急電源，就不需考量突加或者突泄。但是船級社規范里面沒有寫。 糊涂了。