VII Scan text B decide with your partner if the sentences are true or false.

1 The term grounded system means that one leg of the system connects to a

common generator. 2 This common conductor can be the Earth, the skin of the

aircraft, or a structural member of the aircraft.

3 When the grounded leg of the circuit connects to a good electrical conductor, this

conductor can`t serve as one leg of the circuit, cutting out the need for a

separate conductor.

4 Although the grounds are at same points, the potential at same points is the same

since they connect to a common conductor.

5 The letter N doesn`t designate no wire that completes the equipment circuit to the

ground network.

6 Any wire designated as N may come in contact with ground at any point without

causing the equipment to malfunction.

7 Grounding three-wire systems can be done by grounding one of the phases,

usually the B-phase in aircraft.

8 The grounded circuit is better than the ungrounded one because it doesn`t reduce

overall weight by using fewer conductors.

9 This doesn`t result in a reduction in cost and space requirements.

10 Other advantages are that troubleshooting is simplified and the impedance of

the ground return path is higher than that of a run conductor.

11 A disadvantage of a grounded system is that short circuits do not result when a

bare spot on any ungrounded conductor touches ground.

12 Another disadvantage is having circuits of different potentials and frequencies

do not use a common ground.

13 The term ungrounded system means that the circuit connects to ground.

14 The ungrounded system doesn`t have any advantages

15 The system has the disadvantage of adding more weight because it requires

more conductors than the grounded system.

16 Only ungrounded system is used for specific purposes in modern aircraft.

17 Single-phase systems are more complicated design and construction.

18Polyphase systems are of simple in construction and design.

19 These systems are used when high power is required.

20 Single-phase power is not available from polyphase systems.