Three Phase Induction Motor Question & Answers March 3, 2023 By Wat Electrical This article lists 75 Three Phase Induction Motor MCQs for engineering students. All the Three Phase Induction Motor Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up on the fundamentals of the Three Phase Induction Motor. The three-phase induction motors are self-starting motors that run at a constant speed from zero to load. The frame, stator, stator winding, rotor winding, cooling fan, and bearings are the components of three phase induction motor. The stator is a stationary part of an induction motor that consists of a stator winding. The rotor in a three-phase induction is housed on the shaft of an induction motor. The stator current control and stator voltage control are the methods of speed control of an induction motor. The rotor in a three-phase induction motor has two ends one is called the non-driving end and another is called the driving end. Induction motors are widely used power drive that runs at a constant speed. The constant or fixed losses and variable losses are the losses that occur in three phase induction motor. The three-phase induction motors are simple to design, low cost requires minimum maintenance, and has high efficiency & good pf at full load. The squirrel cage induction motor and slip ring induction motors are the type of three-phase induction motors. 1). The armature of both synchronous and DC machines is an example of __________________ winding? Concentrated windings Distributed windings Closed windings Open windings Hint 2). Which one of the following windings is also known as Un bifurcated winding? Mush windings Whole coil windings Distributed windings Half coil windings Hint 3). The hemitropic winding is a type of winding comes under _______________ winding? Single layer winding Double winding Lap winding Wave winding Hint 4). The integral slot and fractional slot come under _______________ winding? Concentric winding Mush winding Lap winding Single layer winding Hint 5). Which one of the following motors always run with lagging power factor? Induction motor Synchronous motor Asynchronous motor All of the above Hint 6). The power range of single-phase squirrel cage motor is _______________? Up to 500 hp Up to 50 hp Up to 15 hp Up to 5 hp Hint 7). The direct-on-line, star delta are the starting methods of an ___________________ induction motor? Slip ring motor Single phase squirrel cage IM Three phase squirrel cage IM Split ring motor Hint 8). The figure shown below is a configuration of derive system for two phase ____________ motor? Two phase IM Single phase squirrel cage IM Three phase squirrel cage IM Split ring motor Hint 9). Which one of the following starting methods for induction motor is simple and inexpensive? Star delta Direct-on-line Soft start Variable frequency drive Hint 10). Which one of the following one controls the motor throughout its operation? Soft starter VFD Autotransformer Direct-on-line starter Hint 11). Which one of the following starting methods for an induction motor has advantage of reduced in rush current and voltage dip? Star delta Direct-on-line Soft start Variable frequency drive Hint 12). The smooth acceleration is an advantage of _________________ starting method of an IM? Primary resistance Wye delta Direct-on-line Part winding Hint 13). The load on the motor is a cause of _________________ losses? Stray load Load related Friction and windage Core Hint 14). Which one of the following is also known as mesh connection? Wye connection Soft starter connection Autotransformer connection Delta connection Hint 15). Which one of the following windings is also called double layer winding? Basket windings Whole coil windings Distributed windings Half coil windings Hint 16). Which one of the following brakes is classified based on drivers' ergonomics? Hand brakes Parking brakes Mechanical brakes Hydraulic brakes Hint 17). ________________ is a type of brake based on basis of actuating method? Foot brakes Hand brakes Hydraulic brakes Parking brakes Hint 18). The efficiency and power factor are high in ________________ induction motor? Three phases Single phase Split phase Permanent split capacitor Hint 19). The permanent single capacitor induction motor is a __________________ phase technique? Split Shaded pole Reluctance SRM Hint 20). Which one of the following is used only for motor start and stop control? Soft starter VFD Autotransformer Direct-on-line starter Hint Three Phase Induction Motor MCQ for Exams 21). The power range of three-phase squirrel cage motor is _______________? Up to 500 hp Up to 50 hp Up to 15 hp Up to thousands of hp Hint 22). The smooth acceleration, reduced mechanical stress are the advantage of _______________ starting method? Star delta Direct-on-line Soft start Variable frequency drive Hint 23). What are the characteristics of brake fluid? Viscosity Boiling point Corrosion resistance All of the above Hint 24). The transient response is fast in ________________ induction motor? Scalar V/F control Vector control IM Both a and b None of the above Hint 25). What are the reasons of an insulation failure in winding burning? System disturbances Excessive load inertia Voltage spikes from VFDs All of the above Hint 26). Which one of the following brakes is classified based on location in the vehicle? Hand brakes Wheel mounted brakes Mechanical brakes Foot brakes Hint 27). Which one of the following is a type of brake based on application of braking effort? Band brakes Servo brakes Disc brakes Drum brakes Hint 28). What are the components of drum type brake system? Braking plate Brake drum Wheel cylinder All of the above Hint 29). The figure shown below is a ____________ phase induction motor? Two phase IM Single phase squirrel cage IM Three phase IM Split ring motor Hint 30). Which one of the following starters does not decreases the starting current? Star delta VFD Autotransformer Direct-on-line starter Hint 31). What are the advantages of three phase induction motor? Simple design Rugged construction Reliable operation All of the above Hint 32). Which class squirrel cage induction motor used for driving intermittent load? Class A squirrel cage Class B squirrel cage Class C squirrel cage Class D squirrel cage Hint 33). What is the standard form of DFIG? Doubly Fed Induction Generator Doubly First Induction Generator Doubly Fed Internal Generator Doubly Fed Integral Generator Hint 34). What are the methods of speed control of an induction motor? Stator current control Stator frequency control Stator voltage control All of the above Hint 35). _________________ are the parts of regenerative braking system? Alternator Inverter Convertor All of the above Hint 36). Which one of the following brakes is classified based on purpose served? Main operational brakes Wheel mounted brakes Transmission mounted brakes Foot, hand brakes Hint 37). The internal expanding brakes classified based on ___________________? Action of brake shoe Based on combinations Based on speciality Based on construction Hint 38). Which one of the following is a type of brake based on construction? Manual brakes Servo brakes Power brakes Drum brakes Hint 39). The figure shown below is a circuit diagram of phase ____________ motor? Two phase IM Capacitor stator Three phase IM Split phase IM Hint 40). What is the standard form of ABS? Anti Braking System Analog Braking System AC Braking System Anti Board System Hint Three Phase Induction Motor MCQ for Quiz 41). The starting torque is low in ___________________ starting method of an IM? Star delta Autotransformer Both a and b Direct-on-line Hint 42). The current flowing through the stator and rotor winding are _______________ losses? Stray load losses Stator copper and rotor copper Friction and windage losses Core losses Hint 43). What is the standard form of DFIM? Doubly Fed Induction Machine Doubly First Induction Machine Doubly Fed Internal Machine Doubly Fed Integral Machine Hint 44). The production cost and torque to current ratio is lower in ________________? PMSM SRM Induction motor None of the above Hint 45). What are the reasons of a frame related mechanical failure? Base plate distortion Foundation Deterioration Foundation size and design All of the above Hint 46). The starting current is very high in ___________________ starting method of an IM? Star delta Direct-on-line Soft start Series reactor Hint 47). The fluctuation in the magnetic field is a cause of _______________ losses? Stray load losses Load related losses Friction and windage losses Core losses Hint 48). What are the disadvantages of delta connection? More torque Efficient Low voltage connection All of the above Hint 49). The figure shown below is a circuit diagram of phase ____________ motor? Two phase IM Capacitor stator PCM motor Split phase IM Hint 50). The primary and secondary windings of a transformer is an example of ________________ winding? Concentrated windings Distributed windings Closed windings Open windings Hint 51). What are the reasons of winding burning? Air gap fault Loose connections Electrical vibrations All of the above Hint 52). The movement of the rotor and air resistance is a cause of _______________ losses? Stray load losses Load related losses Friction and windage losses Core losses Hint 53). The rotor copper loss comes under _______________ losses? Variable Fixed Rotor copper Stator copper Hint 54). What are the advantages of delta connection? More torque Efficient Simple motor design All of the above Hint 55). What are the reasons of a bearing failure in winding burning? Vibration High ambient Fatigue All of the above Hint 56). Which class squirrel cage induction motor used for compressor? Class A squirrel cage induction motor Class B squirrel cage induction motor Class C squirrel cage induction motor Class D squirrel cage induction motor Hint Read more about Induction Motor 57). The reduced in rush current, voltage dip and low cost are the advantages of _____________ starting method? Star delta Direct-on-line Soft start Series reactor Hint 58). The energy efficiency is high in ___________________ starting method of an IM? VFD Primary resistance Direct-on-line Both b and c Hint 59). The figure shown below is a circuit diagram of phase ____________ motor? Two value capacitor motor Shaded pole motor PCM motor Split phase motor Hint 60). Which one of the following windings used for AC commutator machines and DC machines? Concentrated windings Distributed windings Closed windings Open windings Hint Three Phase Induction Motor MCQ for Interviews 61). What are the reasons of a rotor related mechanical failure? Bad mechanical fits Shaft deformation Rotor deflection All of the above Hint 62). Which class squirrel cage induction motor used for constant speed drive such as pump, and blower? Class A squirrel cage induction motor Class B squirrel cage induction motor Class C squirrel cage induction motor Class D squirrel cage induction motor Hint 63). The precise speed control and energy saving are the advantages of ______________ starting method? Star delta Direct-on-line Soft start Variable frequency drive Hint 64). The mechanical stress is high in ___________________ starting method of an IM? VFD Primary resistance Both a and b Direct-on-line Hint 65). The interaction between stator and rotor is a cause of _________________ losses? Stray load Load related Friction and windage Core Hint 66). Which one of the following is also known as star connection? Wye connection Soft starter connection Autotransformer connection Delta connection Hint 67). The stator iron loss comes under _______________ losses? Variable Fixed Rotor copper Stator copper Hint 68). The figure shown below is a circuit diagram of ____________ motor? Two value capacitor motor Shaded pole motor PCM motor Split phase motor Hint 69). The constant power mode of operation is average in _______________ motor? SRM PMSM Induction motor All of the above Hint 70). Which one of the following windings used for AC machines? Concentrated windings Distributed windings Closed windings Open windings Hint 71). What are the reasons of a shaft related mechanical failure? Mounting breakage Shaft alignment Wrong coupling type All of the above Hint 72). Which one of the following windings is also known as half coil winding? Basket windings Whole coil windings Distributed windings Mush windings Hint 73). Which class squirrel cage induction motor used for fan, pump load, etc where torque is low at start? Class A squirrel cage induction motor Class B squirrel cage induction motor Class C squirrel cage induction motor Class D squirrel cage induction motor Hint 74). Which one of the following motors can be run under a wide range of of both leading and lagging? Induction motor Synchronous motor Asynchronous motor All of the above Hint 75). Which one of the following windings is also known as bifurcated winding? Mush windings Whole coil windings Distributed windings Half coil windings Hint For More MCQs Capacitor Start Capacitor Run Motor Question & Answers Induction Motor Question & Answers Reluctance Motor Question & Answers Switched Reluctance Motor Question & Answers DC Motor Question & Answers Synchronous Motor Question & Answers Single Phase Induction Motor Question & Answers Poly Phase Induction Motor Question & Answers Time's up
