Q1. (a) Compare methods of obtaining speed regulation of three-phase induction motor generally used in tankers by means of: (16) i. Rotor resistance. ii. Cascade system. iii. Pole-changing.
Give examples where each system may be employed with advantage.
Q2. a) State the necessary conditions required prior to the synchronizing of electrical alternators. (4)
b) Describe the type of cumulative damage that may be caused when alternators are incorrectly synchronized. (4)
c) Explain how the damage referred to in (b) can be avoided / reduced. (4)
d) For two alternators operating in parallel state the consequences of: (4)
(i) Reduced torque from the prime mover of one machine.
(ii) Reduced excitation on one machine.
Q1. With respect to the High Voltage power systems installation, explain the different types of circuit breaker that are used, comparing them on merits and de-merits. Describe the theory of arc phenomenon and the mechanism fitted to mitigate the arc. (16)
Q9. Briefly discuss the following with respect to safety of navigation:
a) Bridge Navigation Watchkeeping Alarm System (BNWAS) (6)
b) Long Range Identification and Tracking of ships (LRIT). (5)
c) Voyage Simplified Voyage Recorder (VDR/S-VDR) (5)
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