VI Scan the text and decide whether the following sentences are true or false. Discuss them with your partner.

1 Naval aircraft don`t use brushless generators for voltage generation.

2 The advantage of a brushless generator over a brush-type isits decreased

reliability and greater operating time between overhaul.

3 The brushless generator is asalient 10-pole, 9,000-rpm, ac generator.

4 It has a 15-poleac exciter and a four-phase, a wave diode rectifierrotating with

the exciter armature and main generator field assembly.

5 Threehalf-wave rectifiers are on the exciter rotor and connected to the exciter

armature windings.

6 Agenerator shaft shear section doesn`t prevent possible damageto the engine or

drive unit if the generator seizes.

7 A fanat the drive end of the generator provides heatingairflow for the rotor and

stator windings and the drivebearings.

8 All aircraft have oil-cooled generators.

9 Theaircraft engine or gearbox oil enters the generatorthrough an outlet port and

leaves through an exit port inthe mounting flange of the generator.

10 PMG power isrectified and supplied to the exciter field.

11Theelectromagnetic field, built by the excitation currentflowing in the exciter,

induces current flow in therotating three-phase exciter rotor.

12 Two three-phase differential transformers provideprotection against shorts in

the feeder lines between the generator and the bus (called feeder fault).

13 Onetransformer is on the generator. Its coils sense the current flow through

each of the legs that connectthe ground side of the generator stator to ground.

14 Theother transformer is at the second bus and senses currentflow through the

three feeder lines.

15 A device, such as an aircraft engine, that providesthe driving force for a engine,

is a prime mover.

16 The constant frequency is obtained from constant speeddrives such as hydro

mechanical constant-speed drive(CSD) units, air or gas turbines, and the

constant rpmturboprop engine.

17 The hydro mechanical CSD unit converts variableengine speed to a constant

speed output.

18 It holds thefrequency steady to within a few hertz of the desired600 Hz.

19 Load and fault transients limits are within a 580- to 620-Hz range.

20 Thepropeller mechanical governor will hold the generator frequency to 600 ±4

Hz.