Electrical Drives And Controls Set 9

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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