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This set of Electrical Drives and Controls EDC Multiple Choice Questions & Answers (MCQs) focuses on Electrical Drives And Controls Set 9
Q1 | Full form of THD is
- total harmonic diverter
- total harmonic digital
- total harmonic distortion
- total harmonic discrete
Q2 | Calculate the compensator rating required for a sec(Φ)=1.
- 0.64 p.u
- 0.21 p.u
- 0.57 p.u
- 0 p.u
Q3 | Calculate the value of Voltage ripple factor if the Form factor is 1.1.
- 45.8 %
- 46.2 %
- 47.5 %
- 49.9 %
Q4 | Calculate the value of THD if the distortion factor is .8.
- 76 %
- 75 %
- 74 %
- 73 %
Q5 | Full form of VRF.
- voltage ripple factor
- voltage revert factor
- volume ripple factor
- volume revert factor
Q6 | Second lowest order harmonic present in 3-Φ fully controlled rectifier is
- 5th
- 7th
- 3rd
- 2nd
Q7 | The flux and the internally generated voltage of a dc machine is a function of its magneto-motive force.
- non-linear
- linear
- constant
- inverse
Q8 | Choose the best option which identifies about the below characteristics.
- (1)series motor (2) cumulative compound motor (3) shunt motor
- (1)cumulative compound motor (2) series motor (3) shunt motor
- (1)cumulative compound motor (2) shunt motor (3) series motor
- (1)shunt motor (2) series motor (3) cumulative compound motor
Q9 | The speed torque of the differential compound dc motor is shown below. What conclusions can be made?
- this is an unstable machine
- there is regenerative increment in the speed
- this is impractical to be used
- all of the mentioned
Q10 | It is impossible to start a differential compounded dc motor.
- true
- false
Q11 | A student is given a differential compound motor and he has been asked to make it start. How will he try?
- by shorting series field at start
- to run as shunt motor at start
- by making rated current at start
- all of the mentioned
Q12 | For a 100 hp 250 V, compound dc motor with compensating winding has a field current of 5 A to produce a voltage of 250 V at 1200 rpm. What will be the shunt field current of this machine at no load?
- 5 a
- 5.6 a
- 4 a
- 0 a
Q13 | Load torques can be classified into how many types?
- three
- two
- four
- five
Q14 | Rolling mills exhibit what type of load torque characteristics?
- constant torque characteristics
- linearly rising torque characteristics
- non-linearly rising torque characteristics
- non-linearly decreasing torque characteristics
Q15 | What is the relationship between torque and speed in constant type loads?
- torque is independent of speed
- torque linearly increases with increase in speed
- torque non-linearly increases with an increase in speed
- torque non-linearly decreases with an increase in speed
Q16 | Torque inversely varies with the speed in the windage load torque component.
- true
- false
Q17 | What type of force handles for active torques?
- strong nuclear forces
- weak nuclear forces
- gravitational forces
- electrostatic forces
Q18 | Passive torques always oppose the motion of the driven machine.
- true
- false
Q19 | Among the following which one exhibits linearly rising load torque characteristics?
- elevators
- rolling mills
- fan load
- separately excited dc generator connected to the resistive load
Q20 | What is the condition for the steady-state operation of the motor?
- load torque > motor torque
- load torque <<<< motor torque
- load torque = motor torque
- load torque < motor torque
Q21 | Choose the correct one. (* stands for multiplication, J represents the moment of inertia, w represents angular speed).
- j*d(w)/dt = load torque – motor torque
- j*d(w)/dt = load torque + motor torque
- j*d(w)/dt = motor torque – load torque
- j*d(w)/dt = load torque * motor torque
Q22 | Which of the following is the best braking method?
- friction
- electromechanical action
- eddy-currents
- electric braking
Q23 | DC motor is still widely used in tractions due to its excellent braking properties.
- true
- false
Q24 | Which of the following is not the method of electrical braking?
- plugging or counter-current
- dynamic or rheostatic
- regenerative
- eddy current
Q25 | Which of the following is the plugging method of braking?
- reversal of field connections
- reversal of armature connections
- addition of equal and opposite field
- removal of field circuit from current machine circuit