Operate Alternators, Generators. Test 11

What is the purpose of the reverse power relay connected to an AC diesel generator ?

To prevent the generator being run as a motor.
To maintain good load sharing.
To prevent main circuit overload.
To prevent over speeding.

The best way of testing the 'stand-by' function of the emergency diesel alternator is by _____

by switching off the emergency switch board supply breaker on the main switch board.
starting the emergency diesel manually from the spot and check for any leakages or deficiencies.
causing a total black-out on the ship, for example in drydock or when time is available in port.
switching on the 'test run' button on the emergency diesel switchboard.

In the event of total immersion of an electric motor in sea water or oils, what corrective action should you take to make the motor operational again?

Wash with tetrachloride, wipe dry and re-varnish windings.
Clean with air, wash with fresh water and heat by lamp.
Wash with tetrachloride, heat to 80
Wash with fresh water, wipe dry and re-varnish windings.

When an automatic power supply system is provided with an auxiliary diesel stand-by system, and the power supply trips at time ZERO, which of the following is a feasible sequence of activities ?

Time zero: the stand-by diesel starts. + 7 sec: the stand-by diesel runs, + 8 sec: the power is restored.
Time zero + 30 sec: he stand-by diesel starts. + 45 sec: the stand-by diesel runs. + 60 sec : the power is restored.
Time zero + 5 sec: the stand-by diesel starts. + 10 sec: the stand-by diesel runs. + 25 sec: the power is restored.
Time zero + 10 sec: the stand-by diesel starts. + 20 sec: the stand- by diesel runs. + 40 sec: the power is restored.

What will happen when an earth fault occurs on one line of an insulated distribution system?

The line will short circuit with the earth and the line fuse trips.
The system will be in overload and both line fuses trip.
No fuses will trip, the system is isolated from the earth.
The opposite line fuse will trip due to overload.

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