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Electrical Drive Question & Answers

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This article lists 100 Electrical Drive MCQs for engineering students. All the Electrical Drive Questions & Answers given below includes solution and link wherever possible to the relevant topic.

An electrical or electric drive is a system that revolves around the concept of controlling the electrical-based input to mechanical-based power output. This drive comprises sophisticated type electronic systems for controlling the motion of the system. The block diagram of an electrical drive comprises sources like current or voltage, power converters like ADC or DAC, motors like static and dynamic, load like constant or dynamic, sensors like speed, and a controller unit. Where each of them has its individual functionality.

An electrical driver application may vary depending on the zones used. They are mainly used in heavy industrial application areas where a huge load is added along with heavy motors like pumps, paper machines, robots, etc. These drives are also used in smaller loaded areas such as fans, rotors, vehicles, etc. These drives provide higher efficiency up to 98%, are highly reliable, have high speed, high power, perform repetitive tasks, etc. But they limit in terms of breakdowns, occupies larger space, noise, etc.

1). How many components do an electric drive consist of ___ ?
HintAn electric drive consists of 6 components namely motor, electrical machines and loads, sources, power modulator, control unit, sensing unit.
2). A power modulator is classified in to how many types?
HintA power modulator is classified into 5 types namely controlled rectifiers, cyclo converters, DC choppers, AC voltage controllers, and inverters.
3). A controlled rectifier type power modulator is also called______
HintA controlled rectifier is also called AC to DC converters.
4). An inverters type power modulator is also called______
HintAn inverters type power modulator is also called DC to AC converter.
5). An AC voltage controller type power modulator is also called______
HintAC voltage controller type power modulator is also called AC to AC converters.
6). An DC chopper type power modulator is also called______
HintA DC chopper-type power modulator is also called DC to DC converters.
7). An cycloconverter type power modulator is also called______
HintA cycloconverter type power modulator is also called Frequency conversion.
8). A controlled rectifiers provides ____ impedance?
HintA controlled rectifier provides low impedance.
9). A low power type electrical drive is fed with power from ___ phase?
HintA low-power type electrical drive feds power from a single phase.
10). Other type of electrical drive apart from low power is fed with power from ___ phase?
HintOther type of electrical drive apart from low power is fed with power from three phases.
Read more about rectifiers.
11). Which of the following component of power modulator is used for matching power type converter and motor for meeting load requirement?
HintA controller rectifier also called the control unit of power modulator is used for matching power type converter and motor for meeting load requirements.

Electrical Drive Questions and Answers

12). How much power supply is fed to medium and low type power motors?
HintA 400V of power supply is fed to medium and low-type power motors.
13). Which of the following is the voltage value applied to high rated power meters?
HintA 3.3kV, 6.6kV, and 11kV voltage values were applied to high-rated power meters.
14). A sensing unit of electrical driver consist of how many sensing units?
HintA sensing unit of an electrical driver consists of 5 units namely speed sensing, torque-sensing, position sensing, current-voltage sensing, and temperature sensing.
Read more about Torque.
15). Which of the following sensing unit is applied in a tachometer?
HintA speed sensing unit is applied in a tachometer.
16). Which of the following sensing unit is used for measuring wind speed?
HintA tachometer is used for measuring wind speed.
17). Which of the following sensing unit is used for measuring speed and velocity of wind?
HintA speedometer is used for measuring wind and the speed of the wind.
18). Which of the following control unit component is the applications of torque sensing unit?
HintThe control unit component is the applications of the torque-sensing unit is race cars, automobiles, and air crafts.
19). Which of the following is the function of magneto-elastic torque sensor?
HintA torque-sensing is the function of a magneto-elastic torque sensor.
Read more about Tachometer.
20). Which of the following are the applications of position sensing unit?
HintThe applications of position sensing units include Vibro-meter, Rotatory encoder, and GPS.
21). Which of the following is the application of temperature sensing unit?
HintThemistor and Thermometer are the application of temperature sensing unit.
22). An electric driver is classified in to ___ types
HintAn electric driver is classified in to 2 types namely Regenerative and non-regenerative DC drivers.
23). Which of the following is the characteristics of non-regenerative type DC drives?
HintThe characteristics of non-regenerative type DC drives include controls torque in uni-direction and controls the speed of the motor.
24). Which of the following is the characteristics of regenerative type DC drives?
HintThe characteristics of regenerative type DC drives include controls speed is a four-quadrant driver and controls the direction of the motor.
25). Which of the following are enhancements made in an electric drive?
HintThe enhancements made in an electric drive include Slip type control algorithm, Troubleshoots software, and Retarding girds.
26). Which of the following are the dependencies of microprocessor based electric drivers?
HintThe dependencies of microprocessor-based electric drivers include DC motor driver, Traction motor driver, and Induction motor driver.
27). How many phases do a microprocessor based DC motor driver use?
HintA microprocessor-based DC motor driver uses three-phase.
28). Which of the following phase is supplied to microprocessor based DC motor driver?
HintA 3phase AC to AC-DC converter is supplied to a microprocessor-based DC motor driver.
29). Which of the following type of supply current is given as input to microprocessor based DC motor driver?
HintA 3 phase AC type of supply current is given as input to microprocessor-based DC motor driver.
30). Which of the following component of microprocessor based DC motor driver acts as a speed sensor?
HintA techo-generator of microprocessor-based DC motor driver acts as a speed sensor.
31). Which of the following is the predominant feature of an electric drive?
HintThe predominant feature of an electric drive is to obtain maximum output.
32). Which of the following are the applications of electric drivers?
HintThe application of electric drivers is traction systems, cranes, electric cars, etc.
33). Which of the following are the benefits of electric drives?
HintThe benefits of electric drives include easy control, minimum start delay, and remote operation.
34). Which of the following are the features provided by DC motors?
HintThe features provided by DC motors include a field-based mechanical commutator, control of torque, and direct torque measurement.
Read more about rectifiers.
35). Which of the following components in AC motor drive control the speed of motor?
HintThe components in AC motor drive that control the speed of the motor include rectifiers unit, DC circuit, and inverter.
36). Which of the following type of modulation is used for AC motors?
HintA PMW type modulation is used for AC motors.
37). On which of the following factors do AC motors depends on?
HintThe factors AC motors depend on include frequency of incoming AC type power, and No of proles.
38). Which of the following is the formula AC motor speed?
HintThe formula AC motor speed is N=60f/p, where N-speed in RPM, f-frequency, p-no of poles, 60-constant.
39). An electric motor has ___ speed of operation?
HintAn electric motor has a fixed speed of operation.
40). A 4 paired poles of a motor can connect to ___ pair of poles?
41). What is the speed of obtained for 4pairs of poles when connected with its other pairs?
HintThe speed obtained for 4pairs of poles when connected with its other pairs is 1800 RPM.
42). What is the speed of obtained for 8pairs of poles when connected with its other pairs?
HintThe speed obtained for 8pairs of poles when connected with its other pairs is 900 RPM.
43). What is the frequency of operation of Ac motor?
HintThe frequency of operation of the Ac motor is 60Hz.
44). Which of the following method is used for changing speed of AC motor?
HintThe method is used for changing the speed of the AC motor is Adjusting the shunt current field, changing armature current, and increasing poles pairs.
45). Which of the following are the reasons for employing motor drivers?
HintThe reasons for employing motor drivers include energy conversion and process control.
46). An eddy current type driver is also called as_____
HintAn eddy current type driver is also called a dynamic drive.
47). Electric motors generate ___ type of force?
HintAn electric motor generates either rotatory or linear type of force.
48). What is the percentage of efficiency provided by electric motor?
HintThe percentage of efficiency provided by the electric motor is 95%.
49). What is the percentage of efficiency provided by internal combustion engine?
HintThe percentage of efficiency provided by an internal combustion engine is 50%.
50). Who invented the electrostatic type device (electric motor)?
HintAndrew Gordon in 1740 invented the electrostatic type device (electric motor).
51). Which of the following are the advantages of electric drive?
HintThe advantages of the electric drive are enhanced efficiency, ease of control, and long lifespan.
52). Which of the following are the disadvantages of electric drives?
HintThe disadvantages of electric drives include high maintenance, costly and higher power consumption.
53). Which of the following motors are commonly used in an electric drive?
HintDC motor, stepper type motor, brush less type DC motor, DC and AC motors are commonly used.
54). Which of the following are the load components used in an electric drive?
HintThe load components used in an electric drive are machine tools, pump, fan, etc.
55). Which of the following component of electric drive is a component that supplies sufficient power to the drive systems?
HintA controller of the electric drive is a component that supplies sufficient power to the drive systems.
56). Which of the following component of electric drive, provides the inputs to the drive systems depending on control required?
HintThe sensor component of the electric drive provides the inputs to the drive systems depending on the control required.
57). How many types of electrical drives are there based on supply?
HintThere are 2 electrical drives based on supply like AC supply and DC supply.
58). How many types of electrical drives are there based on number of motors?
HintThere are 3 electrical drives based on the number of motors like an individual, multi, and group.
59). How many types of electrical drives are there based on speed?
HintThere are 2 electrical drives based on speed like constant and variable speed drivers.
60). How many types of electrical drives are there based on control parameters?
HintThere are 2 electrical drives based on control parameters like vector, constant power, and constant torque.
61). An AC driver is also labelled as____
HintAn AC driver is also labeled as variable speed drive or variable frequency drive.
62). Which of the following are the components of VSDs drives?
Hintthe components of VSDs drives include rectifying circuits, inductors and capacitors, inverters, and frequency control circuit.
63). A rectifying unit in VSD performs_______
HintA rectifying unit in VSD performs ADC – AC to DC conversion.

Electrical Drive MCQ's for Interviews

64). A LC component in VSD performs_______
HintAn LC component in VSD performs smoothing of the DC waves.
65). A inverter component in VSD performs_______
HintAn inverter component in VSD performs DAC- DC to AC conversion.
66). Which of the following are the advantages provided by VSD?
HintThe advantages provided by VSD include high efficiency, dynamic-based response and initial current consumed is low.
67). Which of the following are the disadvantages of VSD?
HintThe disadvantages of VSD include higher drive system cost and generation of harmony during its operation.
68). Which of the following are the applications of VSD?
HintThe applications of VSD include fans, compressors and crushers.
69). A DC motor are further classified as ______
HintA DC motor is further classified into 2 types digital and analog DC drives.
70). Which of the following electric drive is speed control system?
HintA DC drive classified as an analog and digital DC drive is a speed type control system.
71). Which of the following electric drive is used for controlling the speed of motor?
HintAC drive classified as variable frequency or speed-based electric drive is used for controlling the speed of the motor.
72). Which of the following motor have individual motor for various machine parts?
HintAn individual type motor has an individual motor for various machine parts.
73). Which of the following is an example of individual type motor?
HintA lathe machine is an example of an individual type motor.
74). Which of the following is an example of multi type motor?
HintA crane is an example of multi-type motor.
75). Which of the following is an example of group type motor?
HintA motor with a single shaft machine is an example of group type motor.
76). Which of the following are the examples of constant speed drive type motor?
HintAn example of a constant speed drive type motor is the squirrel cage motor.
77). A constant speed type drive has ___ speed drives
HintA constant speed type drive has static or constant speed drives.
78). A variable speed type drive has ___ speed drives
HintA variable speed type drive has variable speed drives.
79). Which of the following drive minimizes power consumption?
HintA variable speed drive minimizes power consumption.

Electrical Drive Important MCQ's with Hints

80). Which of the following type of control motor provides accurate output compared to voltage frequency drive?
HintA vector CD type of control motor provides accurate output compared to voltage frequency drive.
81). Which of the following parameters are controlled in vector control drive?
HintSpeed and torque parameters are controlled in vector control drive via PWM type modulation within an inverter.
82). Which of the following are the applications of vector control drive?
HintAn induction motor and AC synchronous motor are the applications of vector control drive.
83). Which of the following are the examples of constant torque type drive?
HintExamples of constant torque type drive include screw compressors, feeders, and conveyors.
84). Which of the following are the application of Lathe tool?
HintThe application of Lathe tools is thermal spraying, wood turning and metal spinning.
85). Which of the following objects are generated from lathe?
HintThe objects generated from the lathe include gun barrels, baseball bats, and crankshafts.
86). An induction type motor is also called as____
HintAn induction type motor is also called an asynchronous motor or an AC type electric motor.
87). Which of the following is the configuration of a induction motor?
HintAn induction motor is a contactless motor with a squirrel cage or of wound type.
88). Which of the following are the advantages of a 3-phase squirrel cage type induction motor?
HintThe advantages of a 3-phase squirrel cage type induction motor are economical, self-starters, and reliable.
89). A 1-phase induction motor are used for ___ load
HintA 1-phase induction motor are used for smaller loaded appliances (fans).
Read more about Induction Motor
90). Which of the following is the power factor of loaded induction type motor?
HintThe power factor of the loaded induction type motor can be between 0.85 and 0.90.
91). Which of the following is the power factor of no-loaded induction type motor?
HintThe power factor of a no-loaded induction type motor can be 0.20.
92). Which of the following is the reason for power factor at no-load condition?
HintThe reason for power factor at no-load condition is stator leakage, rotor leakage, and magnetizing reactance.
93). What is the percentage of a windage and friction of an induction motor?
HintThe percentage of a windage and friction of an induction motor is 5 to 15 percent.
94). What is the percentage of a rotor losses of an induction motor?
HintThe percentage of rotor losses of an induction motor is 15 to 25 percent.
95). What is the percentage of a core losses of an induction motor?
HintThe percentage of core losses of an induction motor is 15 to 25 percent
96). What is the percentage of a stray load losses of an induction motor?
HintThe percentage of stray load losses of an induction motor is 10 to 20 percent.
97). What is the full load efficiency percentage of induction motor?
HintThe full load efficiency percentage of induction motor is 85 to 97%.
98). Which of the following are the applications of linear type induction motor?
HintThe applications of linear type induction motors are linear actuator, liquid metal pumping and magnetic levitation.
99). Which of the following are components of induction motor?
HintThe components of the induction motor are bearings, casing, rotor, etc.
100). Which of the following is operation principle of induction motor?
HintElectromotive force is the operation principle of induction motor, where electro motive force is provided across conductors.