Quiz about 301-400

Question 1

301. Two inductor coils in very close proximity; if one of the coils is rotated 90 degrees slowly away from the other the mutual inductance (Level 1)

Accepted Answer

a) Decreases

Answer

b) Remains the same

Answer

c) Increases.

Question 2

302. Two inductor coils in very close proximity; If the angle is 0 degree the magnetic flux which is generated by coil 1 will hit coil 2 in an optimal way. Coil 2 will have: (Level 2)

Accepted Answer

b) The maximum possible voltage

Answer

a) A no voltage.

Answer

c) A lower voltage

Question 3

303. Two inductor coils in very close proximity; If the angle is 45 degree the magnetic flux which is generated by coil 1 will hit coil 2 in an optimal way. Coil 2 will have: (Level 2)

Accepted Answer

c) A lower voltage

Answer

a) A no voltage.

Answer

b) The maximum possible voltage

Question 4

305. Which methods are applied to control the speed of DC machines in practice? (Level 1)

Accepted Answer

a) Voltage control and Field Control

Answer

b) Voltage control

Answer

c) Field Control

Question 5

306. The stationary part of a electrical machine is (Level 1)

Accepted Answer

b) Stator

Answer

a) Magnetic flux

Answer

c) Rotor

Question 6

307. The rotating part of a electrical machine is (Level 1)

Accepted Answer

c) Rotor

Answer

a) Magnetic flux

Answer

b) Stator

Question 7

308. The induced voltage increases proportional to: (Level 2)

Accepted Answer

a) Magnetic field strength, speed of movement and the length of the conductor

Answer

b) Speed of movement, the length of the conductor

Answer

c) Magnetic field strength, speed of movement

Question 8

309. How many part the rotor of a electrical machine has? (Level 2)

Accepted Answer

b) 3

Answer

a) 1

Answer

c) 2

Question 9

310. In a DC motor, the stator's magnetic field, due to armature reaction, moves (Level 2)

Accepted Answer

c) In the opposite direction of rotation of the armature

Answer

a) Into alignment with the GNA

Answer

b) In the same direction of rotation of the armature

Question 10

312. Which statement is correct? (Level 1)

Accepted Answer

c) The stator of a DC machine has a steel ring (yoke), the main poles made of sheet metal with pole core and pole shoe and the excitation winding.

Answer

a) The stator of a DC machine has a steel ring (yoke), the main poles made of sheet metal with pole core

Answer

b) The stator of a DC machine has the main poles made of sheet metal with pole core, pole shoe and the excitation winding.

Question 11

313. Commutating poles are connected (Level 2)

Accepted Answer

b) In series with the armature and hence oppose the armature cross field

Answer

a) In parallel with the armature and hence oppose the armature cross field

Answer

c) In series with the armature and stator

Question 12

315. What is the meaning of peak value? (Level 1)

Accepted Answer

b) The positive or negative maximum value which a sine curve can assume

Answer

a) The positive maximum value which a sine curve can assume

Answer

c) The negative maximum value which a sine curve can assume

Question 13

316. The peak power is calculated by: (Level 2)

Accepted Answer

a) Multiplying the peak voltage Upeak with the peak current Ipeak

Answer

b) Average the peak voltages Upeak

Answer

c) Average the peak current Ipeak

Question 14

318. What is the definition of Triangular Waves? (Level 1)

Accepted Answer

a) Triangular Waves are given if the voltage increases linearly and, if a certain level is achieved, decreases linearly.

Answer

b) Triangular Waves are given if the voltage decreases linearly and, if a certain level is achieved, decreases linearly.

Answer

c) Triangular Waves are given if the voltage increases linearly and, if a certain level is achieved, increases linearly.

Question 15

319. What is the definition of Triangular Waves? (Level 1)

Accepted Answer

b) Triangular Waves are given if the voltage periodically changes between two values

Answer

a) Triangular Waves are given if the current periodically changes between two values

Answer

c) Triangular Waves are given if the voltage no changes

Question 16

320. If the magnetic wheel of a bipolar device (one pole pair) rotates 50 times per second, (Level 2)

Accepted Answer

c) An AC with a frequency of f = 50 Hz is generated

Answer

a) An AC with a frequency of f = 5 Hz is generated

Answer

b) An AC with a frequency of f = 500 Hz is generated

Question 17

321. A sine wave has 5 amps RMS value. What is the peak value? (Level 2)

Accepted Answer

a) 7.07 amps.

Answer

b) 6.37 amps.

Answer

c) 10 amps.

Question 18

322. A sine wave has 10 voltage the peak value. What is RMS value? (Level 2)

Accepted Answer

b) 7.07 V

Answer

a) 14,14 V

Answer

c) 10 V

Question 19

323. The RMS power is calculated by (Level 1)

Accepted Answer

a) Multiplying the RMS voltage V with the RMS current I

Answer

b) Multiplying the Upeak voltage V with the RMS current I

Answer

c) Multiplying the RMS voltage V with the Ipeak

Question 20

324. The symbol for frequency is (Level 1)

Accepted Answer

b) F

Answer

a) H

Answer

c) B

Question 21

326. In a coil with an inductive reactance of XL = 30 Ohm a current of I = 2 A flows. What voltage occurs on the inductive reactance? (Level 1)

Accepted Answer

b) 60 V

Answer

a) 40 V

Answer

c) 50 V

Question 22

328. An ideal coil with an inductance of L = 200 mH is applied to an AC voltage of U = 220, f = 50 Hz, What current builds up? (Level 2)

Accepted Answer

a) 3,5 A

Answer

b) 0.291666666666667

Answer

c) 35 A

Question 23

329. The symbol for reactive power is (Level 1)

Accepted Answer

b) Q

Answer

a) P

Answer

c) A

Question 24

330. The symbol for capacitive reactive power is (Level 1)

Accepted Answer

c) Qc

Answer

a) P

Answer

b) Q

Question 25

331. The reactive power is measured in (Level 1)

Accepted Answer

a) Var

Answer

b) W

Answer

c) KW

Question 26

332. The symbol for apparent power is (Level 1)

Accepted Answer

b) S

Answer

a) P

Answer

c) Var

Question 27

333. The apparent power is measured in (Level 1)

Accepted Answer

c) Volt-Ampere [VA]

Answer

a) Var

Answer

b) KW

Question 28

334. A pure capacitor, inductor and resistor are connected in series and the voltage drops across each are 10V and the total current flowing in the circuit is 1A. How much true power is the circuit consuming? (Level 1)

Accepted Answer

a) 10W

Answer

b) 30VA

Answer

c) 30W

Question 29

337. A coil that has an effective resistance of 12 Ohms and is applied to an AC voltage of 36 V at 50 Hz has a current consumption of 1 A. Calculate the effective voltage. (Level 2)

Accepted Answer

a) 11,88 V

Answer

b) 12 V

Answer

c) 24 V

Question 30

338. A coil that has an effective resistance of 12 Ohms and is applied to an AC voltage of 36 V at 50 Hz has a current consumption of 1 A. Calculate the reactive voltage (Level 2)

Accepted Answer

b) 33,9 V

Answer

a) 25 V

Answer

c) 40 V

Question 31

341. Generally, a transformer consists of: (Level 1)

Accepted Answer

a) Two coils and an iron core

Answer

b) Two cores and a coil

Answer

c) Two cores and an iron core

Question 32

342. The number of windings of the transformer's input coil is (Level 1)

Accepted Answer

b) N1

Answer

a) N1/N0

Answer

c) N2

Question 33

343. The number of windings of the transformer's output coil is (Level 1)

Accepted Answer

c) N2

Answer

a) N1/N1

Answer

b) N1

Question 34

344. The turns ratio of transformer is calculated with this formula (Level 1)

Accepted Answer

a) N1/N2

Answer

b) N3

Answer

c) N2

Question 35

347. An AC transformer converts a voltage of 220 V to 12 V. The secondary coil has 100 turns. How many turns must the primary winding have? (Level 2)

Accepted Answer

a) 1833

Answer

b) 958

Answer

c) 1000

Question 36

348. The secondary winding of a transformer with 60 turns consumes a current of 10 A. How many amperes consumes a primary winding with 1200 turns? (Level 2)

Accepted Answer

b) 0,5 A

Answer

a) 1A

Answer

c) 2A

Question 37

349. A transformer is used to supply four motors. Each motor gives a power of 5 kW. The power factor of the motors is 0.9. What is the minimum nominal power output of the transformer? (Level 2)

Accepted Answer

c) 22,22 W

Answer

a) 20 W

Answer

b) 25 W

Question 38

350. The short circuit voltage of a transformer is (Level 1)

Accepted Answer

a) A reference for the change of the output voltage when the load increases

Answer

b) A reference for the change of the output voltage when the load decreases

Answer

c) A reference for the change of the output voltage when the load no change

Question 39

351. The symbol for the resonance frequency is (Level 1)

Accepted Answer

a) Fres

Answer

b) F

Answer

c) Fr

Question 40

352. A series resonant circuit consists of (Level 1)

Accepted Answer

b) A coil and a capacitor connected in series

Answer

a) A coil and a capacitor connected in parallel

Answer

c) Tow coils and a capacitor connected in series

Question 41

353. In series resonance, which are condition for resonances? (Level 1)

Accepted Answer

c) XL = XC; UL = UC

Answer

a) XL = XC

Answer

b) UL = UC

Question 42

356. The synchronous machines have (Level 1)

Accepted Answer

a) A constant ratio of rotation speed and frequency.

Answer

b) A constant ratio of rotation speed

Answer

c) A constant of frequency.

Question 43

357. The AC generators of airplanes supply an AC voltage with a frequency of 400 Hz. How many pole pairs are necessary in a generator of a B737 which is driven at 6000 rpm? (Level 2)

Accepted Answer

b) 4

Answer

a) 2

Answer

c) 6

Question 44

358. The advantages of a brushless alternator are (Level 1)

Accepted Answer

c) Lower maintenance cost, High stability and consistency of output, better performance at high altitudes

Answer

a) Lower maintenance cost, High stability and consistency of output

Answer

b) High stability and consistency of output, better performance at high altitudes

Question 45

359. A two-phase generator provides 220 V on both the lines.
The phase-to-phase voltage is (Level 2)

Accepted Answer

a) 311 V

Answer

b) 220 V

Answer

c) 155 V

Question 46

360. An alternating current generator is operating at 40 kVA in a circuit with a power factor of 0.9. The real power is (Level 1)

Accepted Answer

b) 36 kVA

Answer

a) 40 kVA

Answer

c) 50 kVA

Question 47

361. The two factors which govern the output frequency of an AC generator are the (Level 1)

Accepted Answer

c) The number of poles (in pairs) and the rotor RPM

Answer

a) Strength of the stator field flux and number of poles

Answer

b) Speed of rotation of the rotor and the stator field flux strength

Question 48

362. In a delta-connected generator (Level 2)

Accepted Answer

a) Line volts = phase volts, line current = root 3 times phase current

Answer

b) Line voltage = root 3 times phase voltage, line current = phase current

Answer

c) Line volts = phase volts, line current = phase current divided by root 3.

Question 49

363. The permanent magnet in an A.C generator induces (Level 2)

Accepted Answer

b) A.C. in the exciter generator

Answer

a) A.C. in the main generator

Answer

c) D.C. in the exciter generator

Question 50

364. If the phase voltage in a star connected generator is 200V what will be the line voltage? (Level 1)

Accepted Answer

c) 346 V

Answer

a) 220 V

Answer

b) 282 V

Question 51

365. A generator is labeled as having 115V/200V, 20A and PF 0.8. What is the apparent power in each line that the generator can produce? (Level 2)

Accepted Answer

a) 4 kVA

Answer

b) 2,3 kVA

Answer

c) 3,2 kVA

Question 52

366. AC generators are rated in (Level 1)

Accepted Answer

b) KVA

Answer

a) KVARs

Answer

c) KW

Question 53

367. There are actually three separate generators within one case (Level 2)

Accepted Answer

c) The permanent magnet generator, the exciter generator, the main generator

Answer

a) The permanent magnet generator, the exciter generator, a rotating rectifier

Answer

b) The exciter generator, the main generator, a GCU

Question 54

368. A 30 KVA rated generator has a power factor of 0.8. What is its maximum consistent power? (Level 1)

Accepted Answer

a) 24 KW

Answer

b) 30 KW

Answer

c) 37.5 KW

Question 55

369. The voltage induced in the stator of an AC generator is produced by (Level 1)

Accepted Answer

b) A rotating magnetic field

Answer

a) An alternating field

Answer

c) A fixed magnetic field

Question 56

370. Permanent magnets in an AC generator are (Level 2)

Accepted Answer

c) To provide initial excitation

Answer

a) To rectify the current

Answer

b) To control the frequency

Question 57

371. In Operation of an Aircraft Generator, If the voltage is too low (Level 2)

Accepted Answer

a) The GCU will increase the exciter field current

Answer

b) The GCU will increase magnetic field

Answer

c) The GCU will reduce the exciter field current

Question 58

372. A synchronous machine consists of (Level 1)

Accepted Answer

a) A stator with a winding and a rotor which also carries a winding

Answer

b) A stator with a winding

Answer

c) rotor which also carries a winding

Question 59

373. The rotating field is generated by (Level 1)

Accepted Answer

b) The rotary current which is connected to the stator windings.

Answer

a) The PMG

Answer

c) The stator windings.

Question 60

374. The synchronous motor is used to (Level 1)

Accepted Answer

c) Achieve a constant rotational speed

Answer

a) Achieve a constant current

Answer

b) Achieve a constant voltage

Question 61

375. An AC motor which rotates at the same speed as supply frequency is called (Level 1)

Accepted Answer

a) A synchronous motor

Answer

b) A universal machine

Answer

c) An induction motor

Question 62

377. A capacitor in a single phase AC motor is to (Level 2)

Accepted Answer

c) Provide a phase shift

Answer

a) Block DC

Answer

b) Prevent spikes

Question 63

379. Calculate the speed of a 400 Hz, 4 pole machine (Level 2)

Accepted Answer

b) 6000 rpm

Answer

a) 12,000 rpm

Answer

c) 8000 rpm

Question 64

380. The stator consists of (Level 1)

Accepted Answer

c) A housing and a laminated core with slots

Answer

a) A housing and carbon brushes

Answer

b) A laminated core with slots and a commulator

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