Exam Question
Explain why EACH of the following protective devices are fitted to a main electrical switchboard
(a) Reverse power (4)
(b) Under voltage (4)
(c) Main circuit breaker overcurrent (4)
(d) Preference trips (4)
Class 4 (4th Engineer)
MET
📅 Jul 2022
Reference Answer
### (a) Reverse Power Protection
**1. Purpose:**
The primary function of a reverse power trip is to protect the prime mover (e.g., diesel engine) of an alternator when operating in parallel with other alternators. It prevents a condition known as 'motoring'.
**2. Principle of Operation:**
**1. Purpose:**
The primary function of a reverse power trip is to protect the prime mover (e.g., diesel engine) of an alternator when operating in parallel with other alternators. It prevents a condition known as 'motoring'.
**2. Principle of Operation:**
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