AC Gen

Question 1

What 3 things are required to produce an EMF by Induction?

Answer 1

Relative movement, magnetic field and conductor.

Question 2

What is the most common type of generator in use today?

Answer 2

Brushless generator.

Question 3

List 2 things that the generated EMF output will depend upon?

Answer 3

The speed at which the lines pass the conductor (freq) and the amount of lines of flux cutting across the conductor(voltage).

Question 4

What is fitted to the AC generator to make it turn? Give examples used in HM Ships.

Answer 4

Prime mover – diesel motor, gas turbine.

Question 5

How is the HF Generator turned, what is its output and where is it fed to?

Answer 5

Drive belt. 1600hz, 115v and 1 phase. Supplies voltage to the windings of AC exciter via AVR.

Question 6

What sort of current is fed into the Exciter Stator?

Answer 6

DC

Question 7

What is the purpose of the Rectifier assembly?

Answer 7

Converts the AC to DC

Question 8

How can the voltage generated by an AC generator be altered?

Answer 8

Increasing or decreasing the strength of the magnetic field.

Question 9

If the magnetic field around the AC Generator Rotor is stable (made from a DC supply), how does the Generator produce and AC output?

Answer 9

As the AC gene rotor is turned by the prime mover the stable magnetic field cuts through the stator windings it produces the AC output.

Question 10

What is the output from Generators fitted to HM Ships and how does the AVR know what’s being produced?

Answer 10

450V, 60hz, 3 phase.