View 335062542multiplechoicequestionsonthreephaseinductionmotor. In ns is the synchronous speed and s the slip, then actual running speed of an induction motor will be a. The rotor of three phase induction motor consists of a cylindrical laminated core with parallel slots that can carry conductors. A 50 hz, 3 phase induction motor has a full load speed of 1440 r. At zero in an induction motor a motor runs as a generator b motor does not run. Three phase ac induction motors are widely used in industrial and commercial applications. Most asked objective questions or mcq on single phase motors.
The 3 phase set of currents, each of equal magnitude and with a phase. If a single phase induction motor runs slower than. Threephase induction motor is mainly suitable for which of the following application a for running different machine tools where several speeds are required b for running paper machine requiring exact speed control c for running electric vehicles d for running rolling mills needing exact speed control. Three phase induction motor mcq questions answers electrical engineering.
Online three phase induction motor mcqs test electrical ride. The stator winding in induction motor corresponds to the primary winding in the transformer and the rotor winding in induction motor corresponds to the secondary winding in the transformer. A threephase induction motor consists of two parts stator the stationary part and rotor the rotatory part with the latter being separated from the former by a small air gap. When three phase stator winding of an induction motor is energized from a 3 phase supply, a rotating magnetic field is set up which rotates around the stator at synchronous speed ns. So that 3 slots in single phase if it is chorded by 2 slot then, out of 3 2 have different phase. Three phase induction motor mcq questions and answers page 3. Rotor of three phase induction motor consists of a cylindrical. The method which can be used for the speed control of induction motor from stator side is. Similarities and differences between induction motor and. In a three phase induction motor, the number of poles in the rotor winding is. Sep 02, 2014 110 top single phase induction motors electrical engineering multiple choice questions and answers latest single phase induction motors questions and answers list 1. A three phase induction motor consists of two parts stator the stationary part and rotor the rotatory part with the latter being separated from the former by a small air gap. Almost 80% of the mechanical power used by industries is provided by three phase induction motors because of its simple and rugged construction, low cost, good operating characteristics, the absence of commutator and good speed regulation. Sep 02, 2014 101 top polyphase induction motors electrical engineering multiple choice questions and answers.
If the frequency of 3 phase supply to the stator of 3 phase induction motor is increased, then. Hindi three phase and single phase induction motors. The induction motor has an induction and a resistor which cause losses. Multiple choice questions on three phase induction motor electric. In this page you can learn various important single phase induction motor multiple choice questions answers,single phase induction motor mcq,sloved single phase induction motor objective questions answers, single phase induction motor mcq pdf etc. At synchronous speed, the slip is zero and hence torque developed by the. Arrangement of stator in 3ph induction motor are given below.
In three phase squirrelcage induction motors a rotor conductor ends are shortcircuited through slip rings b rotor conductors are shortcircuited through end rings c rotor conductors are kept open d rotor conductors are connected to insulation ans. Practice online mcqs on three phase induction motor for electrical engineering job test or interview conceptual question. Polyphase induction motors mcqs for preparation of fpsc, nts, kppsc, ppsc, and other test. An induction motor which connects with a 3 phase supply called 3 phase induction motor. Single phase induction motors the single phase induction motor comes with the different starting arrangements.
The three phase induction motor is the extensively used for various kinds of industrial drives. Speed control in three phase induction motor mcqs with answers. The winding resistance causes copper losses in the windings, the windings inductive resistance cause a voltage drop power factor. The induction motor is similar as a transformer with a rotating shortcircuited secondary. Three phase voltage supplied to the stator windings produces a rotating magnetic field. Most important mcq or objective questions on induction motor are discussed in this page. The hollow shaft can resist more torsion load with the same resisting area same weight as. In the case of three phase ac alternating current operation, the most widely used motor is a 3 phase induction motor, as this type of motor does not require an additional starting device. Multiple choice questions mcq on single phase motors for electrical engineering. Equivalent circuit of three phase and single phase induction motor.
Nov 27, 2019 an electrical motor is an electromechanical device which converts electrical energy into mechanical energy. A stator winding is placed in the stator of induction motor and the three phase supply is given to it. Equivalent circuit of induction motor for 3 phase and. One single phase wattmeter plus miscellaneous apparatus as needed. Rotor of three phase induction motor consists of a. The stator of an induction motor consists of 3 phase windings, which when connected to a 3 phase supply creates a rotating magnetic field. If the capacitor of a single phase motor is shortcircuited.
May, 2020 26 thoughts on 100 most important 3phase induction motor mcq with explanation polyphase induction motor mcq with explanation gutte sushan december, 2017 at 3. They run at a constant speed from noload to the full load. The more we add carbon in steel, the more it becomes harder and stronger. Multiple choice questions on three phase induction motor free download as word doc. It has high starting torque like 2 times the full load torque. Working principle of 3phase induction motor electrical. When the 3 phase stator windings are fed by 3 phase supply, a magnetic flux of constant magnitude which is rotating at synchronous speed is set up.
The torque developed by an induction motor is proportional to the slip. Aug 21, 2015 3 phase induction motors related mcq objective questions with answers 1 which of the following statements about a three phase squirrelcage induction motor are false. In a three phase induction motor a power factor at. Induction motors interview questions and answers mcqs. In a split phase motor, the running winding should have a high res. Single phase induction motor multiple choice questions mcq. A portion of rotating magnetic field in a three phase. Induction motor important mcq questions part 1 youtube. Construction of three phase induction motor electrical4u. Dol is used for controlling this high starting current to the motor. Induction motor objective questions with answers objectivebooks. Three phase induction motor mcq questions answers electrical. And the induction motor, especially the three phase induction motor, has two types of equivalent circuits which are.
If one of the parallel resistors in any parallel circuit is removed from the circuit, then the total resistance a doubled b increases c remains the same d decreases answer. It is widely used when compared to the three phase motor for the industrial, commercial and domestic purposes. Explain starting methods of 3 phase induction motor. In a three phase induction motor a power factor at starting is high as compared to that while running. Induction motor seminar ppt, pdf report study mafia. Apr 17, 2019 mcq on induction motor electrical 3 phase induction motor mcq pdf induction motor question bank rotor of three phase induction motor.
Dec, 2018 electrical engineering three phase induction motor objective types question and answer in hindi in this video we know about 25 important 25 objective questions with their answer in hindi which. The flux passes through the airgap and sweeps past the rotor surface thus it cuts the rotor conductors. Three phase induction motor introduction basic electrical. Three phase induction motors mcqs with explanatory answers 1. When the rotor of 3 phase induction motor run at synchronous speed, its rotor frequency will become a. Single phase induction motors multiple choice questions. Similarities between induction motor and transformer. Multiple choice question mcq of induction motors page1. M motor mcq three phase induction motor click here to download pdf of 3phase i. When a three phase supply is given to the three phase stator winding, a rotating magnetic field of constant magnitude is produced as discussed earlier. This starter is mostly used for less than 5 kw rating motors. In three phase induction motor, the power is transferred from stator to.
The indus3 series general purpose ac three phase induction motors have been designed and engineered in compliance with latest technical knowledge and production processes and has attained highest standards in both the fields. Rotor ohmic loss a squirrel cage induction motor is 4 kw at slip 0. Generally, there are two types of the induction motors known as single phase and three phase induction motors. In a three phase induction motor, the number of poles in the. Polyphase induction motors mcq question is the important chapter for a electrical engineering and gate students. Oct 18, 2019 dc generator click here to download dc motor click here to download single phase induction motor click here to download pdf of 1phase i. Torque equation of threephase induction motor electrical.
Starting method for induction motors a 3 phase induction motor is theoretically self starting. Induction motors have high starting current like 6 to 8 times the rated current. The three phase induction motor is the most widely used electrical motor. Ppt threephase induction motor electrical engineering. Latest single phase induction motors questions and answers list 1. Induction motor basics, single phase and three phase. Ac induction motors are also the most common motors used in main powered home appliances. Home category electrical engineering mcq questions and answers 3 phase induction motors. As shown in equation 4, the developed torque depends on the air gap power and synchronous speed. It can be very help full for your electrical engineering exam or competitive exams. Electrical engineering three phase induction motor objective.
It consists stator winding it is housed on the motor frame. The three phase induction motor has voltage applied to the stator that creates a rotating flux wave. Three phase induction motors mcqs with explanatory answers. Home category electrical engineering mcq questions and answers 3 phase induction motors 1 the frequency of the induced emf in an induction motor is a. Slip, s, is defined as the difference between synchronous speed and operating speed, at the same frequency, expressed in rpm, or in percentage or ratio of synchronous speed. Three phase induction motors questions and answers sanfoundry. Like any electric motor, a 3phase induction motor has a stator and rotor. Polyphase induction motors mcqs for preparation pakmcqs. This video provides all the important mcq questions from induction motor in detail and also provides some important points to remember for interviews and exams induction motor important mcq. Three phase ac circuits mcqs with explanatory answers. Twice of the maximum value of flux due to any phase. If the frequency of 3phase supply to the stator of 3phase induction motor is increased, then. Carbon steel is the appropriate choice for making the shaft of an induction motor.
The crawling word it selfsuggest crawl means moving with low speed this characteristic is the result of improper functioning of the motor that means either motor is running at very slow speed or it is not taking the load. Jan 02, 2020 an induction motor is a single excited machine. Apr 11, 2020 ssc je electrical important mcq pdf part 3 notedownload link of pdf given at end of post 1. Speed control in three phase induction motor mcqs with.
Ppt threephase induction motor electrical engineering ee. Three phase induction motor mcq solve three phase induction motor mcq,here given lots of unique mcq for you. The main drawback of dc motors is the presence of commutator and brushes, which require frequent maint. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. Three phase induction motor is a generally selfstarting motor. Single phase induction motors mcqs for preparation pakmcqs. The basic idea of an electric motor is to generate two magnetic fields. If the frequency of 3phase supply to the stator of 3phase induction motor is increased, then breaking news. Stator is made up of number of stampings in which different slots are. In a 3 phase ac induction motor, there are three stator windings, each usually in two halves, with the rotor winding shortcircuited by end rings. Nov 27, 2019 the three phase induction motor is the most widely used electrical motor. The field of an induction motor rotor rotates relative to the stator at.
Y2 series three phase induction motors dimensions and rated output are in conformity with international standard iec 600721. In a split phase motor, the running winding should have a high resistance and low inductance b low resistance and high inductance c high resistance as well as high inductance d low resistance as well as low inductiance ans. Record all nameplate information for the induction motor. Three phase induction motor electrical engineering mcq questions answers. This torque is differs from the torque actually available at the terminals by the friction and windage torque in the induction motor. You should also make a dc measurement of stator winding linetoline resistance. Speed control in three phase induction motor mcqs with answers q1. The rotor will constantly be turning to align its magnetic field with that of the stator field. Polyphase induction motor mcq with explanation in case of 3 phase induction motors the ratio of core length to pole pitch for minimum cost is taken as. The conductors are heavy copper or aluminum bars fitted in each slot and shortcircuited by the end rings. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain.
Its main function is to support the stator core and the field winding. In three phase induction motors sometimes copper bars are placed deep in the rotor to a improve starting torque b reduce copper losses c improve efficiency d improve power factor ans. The working of the threephase induction motor is based on the principle of electromagnetic induction. Single phase induction motor multiple choice questions. Stator frame it is the outer most part of the three phase induction motor. Working principle of 3 phase induction motor eduction motor works on the principle of electromagnetic induction. The method which can be used for the speed control of induction motor from stator. These motors are selfstarting and use no capacitor, start winding, centrifugal switch or other starting device. As the current passes through the coils on opposite sides of the stator, a twopole electromagnet is established, creating a twopole motor. Mcq on induction motor page 7 electrical study app. As that wave sweeps by the rotor bars, voltages are induced. Polyphase induction motor mcq with explanation in case of 3 phase induction motors the ratio of core length to pole pitch for minimum cost is. As its name indicates stator is a stationary part of induction motor. These are of two types, squirrel cage and slip ring motors.
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