Exam Question
Which of the following devices will prevent a DC generator from becoming motorized?
(a) Over current relay
(b) Motorization trip
(c) Reverse power relay
(d) Reverse current relay. Why the remaining options were not considered.
Class 2 (2nd Engineer)
MET
📅 Jul 2018
Reference Answer
The correct answer is: (d) Reverse current relay
A reverse current relay is specifically designed to prevent a DC generator from becoming motorized. If the generator loses its prime mover (e.g., due to fuel loss), its voltage drops. When operating in parallel, the other generator(s) in the system will cause current to flow back into the faulty generator, leading to reverse current. The reverse current relay detects this and trips the circuit breaker, protecting the generator from damage.
Reasons for not considering other options:
Overcurrent Relay (a):
A reverse current relay is specifically designed to prevent a DC generator from becoming motorized. If the generator loses its prime mover (e.g., due to fuel loss), its voltage drops. When operating in parallel, the other generator(s) in the system will cause current to flow back into the faulty generator, leading to reverse current. The reverse current relay detects this and trips the circuit breaker, protecting the generator from damage.
Reasons for not considering other options:
Overcurrent Relay (a):
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