MCQ in Power Generators (Cells and Batteries) Part 6 | ECE Board Exam

This is the Multiples Choice Questions Part 6 of the Series in Power Generators, Sources, Principles and Applications as one of the Electronics Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.

MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in Cells and Batteries
• MCQ in Electric Generator
• MCQ in Electronic Power Supply
• MCQ in Voltage Regulation
• MCQ in Photovoltaic/Thermoelectric Generator
• MCQ in Distribution Transformer
• MCQ in Uninterrupted Power Supply (UPS)
• MCQ in Float-Battery System
• MCQ in Converters
• MCQ in Inverters

Continue Practice Exam Test Questions Part 6 of the Series

Choose the letter of the best answer in each questions.

251. What is the voltage regulation when the full load voltage is the same as no-load voltage assuming a perfect voltage source?

A. 100%

B. 1%

C. 10%

D. 0%

252. Calculate the voltage regulation of a generator having a no-load voltage of 220 V and a full load voltage of 180 V.

A. 18%

B. 22%

C. 28%

D. 32%

253. Usually used to drive low-speed alternators

A. diesel engines

B. jet propulsion engines

C. steam turbines

D. hydraulic turbines

254. Is usually used to drive high-speed alternators

A. diesel engines

B. pneumatic engines

C. steam turbines

D. hydraulic turbines

255. Which statement is true regarding alternators?

A. high-speed alternators are smaller than low-speed

B. low-speed alternators are smaller than high-speed

C. high-power alternators are smaller than low-power

D. high-voltage alternators are smaller than low-voltage

256. For what reason, why carbon brushes are widely used dc machines?

A. it is abundant

B. it is cheap

C. it has a high voltage drop

D. it lubricates and polishes the contacts

257. Alternators have less chance to hunt if driven by

A. steam turbines

B. hydroturbines

C. diesel turbines

D. nuclear reactor

258. In alternators, what is the purpose of damper windings?

A. it prevents over speeding

B. it maintain constant speed

C. it prevents hunting

D. it protects overloading

259. What term applies to the use of two or more generators to supply a common load?

A. on-line operation

B. series operation

C. cascaded operation

D. parallel operation

260. In paralleling ac generators, ________ is very important.

A. voltage level

B. current level

C. phase angle

D. internal resistance

261. Description used for generators trying to self-adjust its parameters before paralleling with on line generators.

A. synchronizing

B. sequencing

C. jogging

D. alighning

262. In changing power from one generator to another, what do you call the operational sequence wherein the incoming generator is connected first before removing the existing generator?

A. No Break Power Transfer (NBPT)

B. UPS

C. LIFO

D. Standby Power transfer

263. What do you mean by break power transfer?

A. The incoming generator will be connected first to the bus bar before disconnecting the existing generator.

B. The present on-line generator will be disconnected first before connecting the incoming generator.

C. The incoming generator will only be connected to the bus bar when the bus bar breaks.

D. The present on-line generator will be disconnected first and then reconnected together with the incoming generator.

264. How alternators rated?

A. in Watts

B. in kW

C. in kVar

D. in kVA

265. In electrical power distribution, what do you call the first distribution line from the main generating station?

A. main transmission lines

B. primary distribution lines

C. sub transmission lines

D. secondary distribution lines

266. The lines which carry the energy from the transformer to a customer’s services are called ________.

A. main transmission lines

B. primary distribution lines

C. sub transmission lines

D. secondary distribution lines

267. In electrical power Generating/distribution Company, which do you think is their highest expenses?

A. generation of power

B. distribution of power to the consumers

C. power transmission

D. substations

268. In electrical power distributions, what insulator is generally used?

A. rubber

B. wood

C. plastic

D. porcelain

269. Electrical machines refer to machines that convert ________.

A. mechanical to electrical energy

B. electrical to mechanical energy

C. electrical energy of one form to electrical energy of another form

D. all of the above

270. Electrical machines that convert electrical energy to mechanical energy.

A. generators

B. motors

C. rotary converters

D. frequency converters

271. Synchronous type of ac-motor,

A. uses a dc-generator to supply dc-excitation to the rotating field

B. uses pulsating dc

C. uses alternator

D. has an ac or dc depending on the type of machine

272. Generally in dc motors

A. the armature winding is rotated by a stationary magnetic field produced by electromagnets or permanent magnets.

B. current is sent into the armature winding; or the armature winding is usually placed in a stationary laminated iron core and the rotating element may or may not be a set of magnet poles, it depends on the type of motor.

C. the electromagnets or permanent magnets (magnetic fields) are rotated with respect to the stationary armature winding.

D. the armature winding is supplied with current; or the armature is placed inside a set of radially supported magnetic poles.

273. In ac motors, generally

A. current is sent into the armature winding; or the armature winding is usually placed in a stationary laminated iron core and the rotating element may or may not be a set of magnet poles, it depends on the type of motor.

B. the armature winding is supplied with current; or the armature is placed inside a set of radially supported magnetic poles.

C. the armature winding is rotated by a stationary magnetic field produced by electromagnets or permanent magnets.

D. the electromagnets or permanent magnets (magnetic fields) are rotated with respect to the stationary armature winding.

274. Among the dc motors, which produces the highest torque?

A. series

B. shunt

C. compound

D. differentially compounded

275. Dc motor that has the most stable speed.

A. differentially compounded

B. compound

C. shunt

D. series

276. In dc motors, when does severe arcing happens?

A. during starting

B. during rated speed

C. during speed fluctuation

D. during shutdown

277. What is the primary reason why carbon brushes are preferred over copper brushes in dc motors?

A. they have low loss

B. they are more strong

C. they produce less arcing

D. all of the above

278. In dc motors, the emf developed which opposes to the supplied voltage.

A. residual emf

B. induced emf

C. coercive emf

D. counter emf or back emf

279. To minimize arcing during starting of dc motors, a resistance should be added to limit the current in the ________.

A. series field winding

B. shunt field winding

C. armature winding

D. all of these

280. Which dc motors whose speed is greatly affected by a change in load? It will even run away if the load is removed.

A. series

B. shunt

C. cumulatively compounded

D. differentially compounded

281. Motors whose speed can be easily controlled.

A. dc motors

B. ac motors

C. ac & dc motors

D. ac or dc motors

282. When a dc motor has no load, what will happen to the back emf?

A. reduces

B. increases

C. becomes maximum

D. becomes zero

283. When can we get a maximum mechanical power from a dc motor?

A. Eb = 0

B. Eb = ½V

C. Eb = 1V

D. Eb = 2V

284. The torque of a dc motor is

A. directly proportional to the field strength

B. inversely proportional to the field strength

C. directly proportional to the armature current

D. A and C are correct

285. One causes why the shaft torque is less than the developed armature torque of a dc motor.

A. eddy current

B. field loss

C. brushes loss

D. friction loss

286. For heavy-duty dc motor, how does the effect of armature reaction be corrected?

A. using interpoles & brush shifting

B. using interpoles

C. using compensatory winding

D. B & C are correct

287. Considered as a variable speed motor

A. compounded

B. differentially compounded

C. shunt

D. series

288. What is the most common method used in varying the speed of a dc motor?

A. by varying the supply voltage

B. by changing the effective number of conductors in series

C. by varying the armature resistance

D. by varying the field strength

289. The running speed of a dc series motor is greatly affected by what factor?

A. field excitation

B. load

C. armature resistance

D. supply voltage

290. In choosing a motor for a particular application, what characteristic you should consider?

A. speed-torque

B. speed-armature current

C. speed efficiency

D. speed power

291. What will happen to the dc shunt motor if the load torque greatly increases?

A. the speed will decrease

B. there will be a great increase in current

C. the speed almost remains constant

D. B and C are correct

292. What will happen to a dc series motor when its load is removed?

A. the motor will stop

B. the motor speed remains the same

C. the torque remains the same

D. the motor will overspeed

293. A motor whose speed increases as the load is increased.

A. series dc

B. dc shunt

C. cumulatively compounded

D. differentially compounded

294. Factor(s) that affect iron losses in a dc motor.

A. flux

B. speed

C. armature resistance and flux

D. A and B are correct

295. One advantage of a cumulatively compounded motor is that it does not run widely at light loads, this feature is due to

A. shunt winding

B. brake winding

C. series winding

D. clutch winding

296. In applications where an almost constant speed is required, a _______ motor is a good choice.

A. dc shunt

B. dc series

C. cumulatively compounded

D. differentially compounded

297. In applications where a high torque is needed during starting a _______ motor is preferred.

A. dc shunt

B. dc series

C. differentially compounded

D. cumulatively compounded

298. In applications where sudden heavy loads happen for short duration, a _______ motor is the best choice.

A. dc shunt

B. dc series

C. cumulatively compounded

D. differentially compounded

299. In motors of the same rating, which has the least starting torque?

A. dc shunt

B. dc series

C. differentially compounded

D. cumulatively compounded

300. Factor(s) that affect friction and winding loses in dc motors.

A. speed

B. armature current

C. interpoles

D. armature resistance

Questions and Answers in Power Generators, Sources, Principles, Applications

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Complete List of MCQ in Electronics Engineering per topic