Electrical Drives MCQ

Electrical Drives MCQ

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  • 17th Apr, 2021

Electrical Drives MCQ Test

Following are mostly asked Electrical drives MCQ test that are designed for professionals like you to crack you interviews. You can take this Electrical drives online test before appearing to you real interview. This Electrical drives quiz there are around 30+ multiple choice questions on Electrical drives with four options.

1) To save energy during braking-----------------braking is used?

  • A.  dynamic
  • B.  plugging
  • C.  regenerative
  • D.  all of the above

2) The concept of V/f control of inverters driving induction motors resuls in

  • A.  constant torque operation
  • B.  speed reversal
  • C.  reduced magnetic loss
  • D.  hormonic elimination

3) Which of the following are electrical braking methods ?

  • A.  plugging
  • B.  dynamic
  • C.  regenerative
  • D.  all of the above

4) ———– was the first city in India to adopt electric traction.

  • A.  Delhi.
  • B.  Madras.
  • C.  Calcutta.
  • D.   Bombay.

5) Which of the following state capital is not on broad gauge track?

  • A.  Lucknow.
  • B.  Bhopal.
  • C.  Jaipur.
  • D.  Chandigarh.
Download Free : Electrical Drives MCQ PDF

6) Which braking is not possible in series motor?

  • A.   Regenerative braking.
  • B.   Dynamic braking.
  • C.   Counter current braking.
  • D.   Rheostat braking.

7) Polarity of supply voltage is reversed in which type of braking?

  • A.   Regenerative braking.
  • B.   Dynamic braking.
  • C.   Plugging.
  • D.   None of these.

8) In industries which electrical braking is preferred?

  • A.   Regenerative braking.
  • B.   Plugging.
  • C.   Dynamic braking.
  • D.   None of the above.

9) Full form of VVVF control

  • A.   variable voltage VAr frequency.
  • B.   VAr variable voltage frequency.
  • C.   variable VAr voltage frequency.
  • D.   variable voltage variable frequency.

10) What type electric drive is used in cranes?

  • A.  Multimotor.
  • B.  Group.
  • C.  Individual.
  • D.  Both A and C.

11) An elevator drive is required to operate in

  • A.   one quadrant only.
  • B.   two quadrants.
  • C.   three quadrants.
  • D.   four quadrants.

12) Electric drive is becoming more and more popular because

  • A.   all of below.
  • B.   it provide smooth and easy control.
  • C.   it is cheaper in cost.
  • D.   it is simple and reliable.

13) The basic elements of a electric drive are

  • A.   electric motor.
  • B.  control system.
  • C.   electrical motor and control system.
  • D.   none of the above.

14) Speed control by variation of field flux results in

  • A.   constant power drive.
  • B.   constant torque drive.
  • C.   variable power drive.
  • D.   none of the above.

15) A four quadrant operation requires

  • A.  two full converters in series.
  • B.  two full converters connected in parallel.
  • C.  two full converter connected in back to back.
  • D.  two semi converters connected in back to back.

16) A motor has a thermal heating time constant of 50 mm. When the motor runs continuous of full scale, its final temperature rise is 80° C, what would be the temperature rise after 1 hour, if the motor runs continuously on full load?

  • A.   55.9 ° C.
  • B.  58° C.
  • C.  56° C.
  • D.  60° C.

17) In 4 quadrant operation of a hoist 3rd quadrant represents

  • A.   reverse motoring.
  • B.   reverse braking.
  • C.   forward braking.
  • D.   forward motoring.

18) High braking torque produced in

  • A.   plugging.
  • B.   dynamic braking.
  • C.   regenerative braking.
  • D.   none of above.

19) In case of kiln drives, starting torque is.

  • A.   more than double of the running torque.
  • B.   more than triple of the running torque.
  • C.   almost equal to running torque.
  • D.   less than running torque.

20) What are the constituents in speed time curve of train?

  • A.   Coasting.
  • B.   Initial acceleration.
  • C.   Constant speed.
  • D.   All of these.

21) Which speed control method preferred for constant torque drive?

  • A.  Field control.
  • B.   Armature voltage control.
  • C.  Mechanical loading system.
  • D.  None of above.

22) While operating on variable frequency supplies, the AC motor requires variable voltage in order to

  • A.  protect the insulation.
  • B.   avoid effect of saturation.
  • C.  improve the capabilities of the inverter.
  • D.  protect thyristor from dV / dt.

Electrical Drives Online Test Questions (Electrical Drives FAQs)

1) What is an electrical drive?

An electrical drive is an equipment or machine that works on electricity. It basically converts electrical energy into mechanical energy.

2) List some applications of electrical drive?

Some applications of the electrical drive are:

  • transportation systems
  • conveyors
  • robots
  • hydraulic & electric motors
  • diesel engines

3) What are AC and DC drives?

AC drives stand for Alternating Current drive that is used to control the frequency and variable speed.

DC drives stand for Direct Current Drive which is used to convert alternating current into direct current.

4) What are different parts of electrical drives?

The main parts of the electrical drives are:

  • power modulator
  • controlling unit
  • sensing units

5) In electrical drives load torques can be classified into how many types?

In electrical drives load torques can be classified into two types that are:

  • active load torques
  • passive load torques

6) What is regenerative braking?

Regenerative braking is a technique used to convert the kinetic energy of an electric vehicle into stored energy in the vehicle's battery by slowing down the vehicle by applying breaks.

7) What are different modes of operation in electrical drives?

There are three different modes of operation in electrical drives:

  • Steady-State
  • Acceleration including starting
  • Deceleration including stopping

8) What is self-control mode of synchronous motors?

The self-controlled mode of synchronous motors changes the supply frequency so that the synchronous speed remains the same as that of the rotor speed.

9) What is brushless DC motor?

A Brushless DC motor does not contain permanent magnets on the outside of its structure instead, the permanent magnets are fixed on the rotor and the electromagnets are fixed on the stator.

10) What is Power modulator?

The power modulator is used to regulate the output power of the source and controls the power from the source to the motor is such that the motor transmits the speed-torque characteristic as per the requirement of the load.

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