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. Describe with the aid of a simple sketch the arrangement of the three-phase winding of an alternator showing the neutral point. Explain why for most ships the neutral point is insulated. Explain why in some installation the neutral point in earthed. (16)
Q1.a) Explain the meaning of the term power factor correction (4)
b) State advantages of power factor correction (4)
c) Explain, with the aid of a circuit diagram, how power factor correction can be effected in a three phase circuit using capacitors. (4)
d) Explain one method other than the use of capacitors by means of which power factor correction may be effected. (4)
Q4. (a) Explain why it is necessary to have reverse power protection for alternators intended for parallel operation (6)
(b) (i) Sketch a reverse power trip (5)
(ii) Explain briefly the principle on which the operation of this power trip is based and how tripping is activated (5)
Q2. a) Explain why it is necessary to have reverse power protection for alternators intended for operation. (6)
b) (i) Sketch a reverse power trip. (5)
(ii) Briefly explain the principle on which the operation of this power trip is based and how tripping is activated. (5)
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