Question 49Electricity & Electronics - 1st Asst/Chief

70% to pass

After a black out onboard and once ships power has been restored, the engine room supply fans must be started manually. What characteristic of the electrical circuit for the supply fans cause this requirement?

AThe thermal overload has tripped and must be reset.
BThe circuit for the supply fan is wired for low voltage release.
CThe main breaker for the supply fan on the switchboard has tripped and must be reset manually.
DThe circuit for the supply fan is wired for low voltage protection.
AI Explanation

The correct answer is D) The circuit for the supply fan is wired for low voltage protection. The reasoning behind this is that electrical circuits for critical equipment like engine room supply fans are often designed with low voltage protection. This means that if the main power supply is lost, causing a blackout, the circuit will automatically disconnect the equipment to prevent damage when the power is restored. The fan must then be manually restarted once power has been restored, as the low voltage protection circuit will not automatically reconnect the equipment. The other options are incorrect because they do not accurately describe the underlying reason for the manual restart requirement. Option A is incorrect as a thermal overload would not cause this behavior. Options B and C describe different circuit behaviors that are not relevant in this case.

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