Electrical Drives And Controls Set 8

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This set of Electrical Drives and Controls EDC Multiple Choice Questions & Answers (MCQs) focuses on Electrical Drives And Controls Set 8

Q1 | The value of slip at which maximum torque occurs  
  • r2÷x2
  • 4r2÷x2
  • 2r2÷x2
  • r2÷3x2
Q2 | AC voltage controllers convert
  • fixed ac to fixed dc
  • variable ac to variable dc
  • fixed ac to variable ac
  • variable ac to fixed ac
Q3 |   devices were used for voltage control applications.
  • cycloconverters
  • vacuum tubes
  • tap changing transformer
  • induction machine
Q4 |   applications.
  • power generation
  • electric heating
  • conveyor belt motion
  • power transmission
Q5 | In the principle of phase control
  • the load is on for some cycles and off for some cycles
  • control is achieved by adjusting the firing angle of the devices
  • control is achieved by adjusting the number of on off cycles
  • control cannot be achieved
Q6 | consists of
  • one scr is parallel with one diode
  • one scr is anti parallel with one diode
  • two scrs in parallel
  • two scrs in anti parallel
Q7 | The below shown controller circuit is a
  • half wave controller
  • full wave controller
  • none of the mentioned
  • will depend upon the firing angle
Q8 | The below given controller circuit is a
  • half wave controller
  • full wave controller
  • none of the mentioned
  • will depend upon the firing angle
Q9 | circuit
  • only the negative cycle can be controlled
  • only the positive cycle can be controlled
  • both the cycles can be controlled
  • none of the mentioned
Q10 | Which motor is preferred for Jaw crushers?
  • wrim
  • scim
  • belt slip ring im
  • dc shunt motor
Q11 | A high starting torque is offered by the Belt Conveyors.
  • true
  • false
Q12 | Which starting method is the worst method in Induction motor?
  • direct online starting
  • autotransformer starting
  • reactance starting
  • star-delta starting
Q13 | The capacity of the Crane is expressed in terms of tonnes.
  • true
  • false
Q14 | 1800 second rated motors are used for
  • heavy duty cranes
  • light duty cranes
  • medium duty cranes
  • intermittent duty cranes
Q15 | Calculate the frequency of the rotor side of the IM if the value of slip is 0.34 and the supply frequency is 70 Hz.
  • 23.8 hz
  • 22.7 hz
  • 24.5 hz
  • 23.1 hz
Q16 | Calculate the resonant frequency if the values of the capacitor and inductor are 4 F and 4 H.
  • .25 rad/sec
  • .26 rad/sec
  • .28 rad/sec
  • .29 rad/sec
Q17 | Calculate the value of the angular acceleration of the Heavy duty crane using the given data: J = 5 kg-m2, load torque = 30 N-m, motor torque = 80 N-m.
  • 10 rad/s2
  • 20 rad/s2
  • 30 rad/s2
  • 50 rad/s2
Q18 | The direction of the single-phase IM can be reversed by using which one of the method?
  • by interchanging the supply terminals
  • by removing the capacitor
  • by changing the direction of auxiliary winding current
  • by removing the main winding
Q19 | Which motor is preferred for overhead traveling cranes?
  • intermittent periodic motor
  • continuous duty motor
  • slow speed duty motor
  • short time rated motor
Q20 | Which test is used to determine the conditions where electric motors are being used?
  • thermography
  • geography
  • seismography
  • anthropology
Q21 | What is the range of size of the motor (kW) for efficiency nearly equals to 90%?
  • 15-150
  • 0-2
  • 3-15
  • 150-250
Q22 | Calculate the heat loss in the electric motor for time interval 0-5 sec using the following data: Ia=2 A, Ra=.8Ω.
  • 16 j-sec
  • 14 j-sec
  • 12 j-sec
  • 10 j-sec
Q23 | 1 Btu/h is equal to                        
  • .641
  • .334
  • .293
  • .417
Q24 | Overloading can be prevented using
  • over-current protection
  • speed protection
  • over frequency protection
  • oversize protection
Q25 | Full form of IDMT is                    
  • inverse definite minimum time
  • inverter definite minimum time
  • inverter definite maximum time
  • insert definite minimum time