The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be
Last Answer : The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be 0.5 Ohm
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1 answer
asked
May 3, 2018
by
anonymous
Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.
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141 views
0 answers
asked
Apr 16, 2020
by
anonymous
Ratio of the rotor reactance X to the rotor resistance R for a two-phase servo motor (A) is equal to that of a normal induction motor (B) is less than that of a normal induction motor (C) ... than that of a normal induction motor (D) may be less or greater than that of a normal induction motor
Last Answer : C
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583 views
2 answers
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Apr 28, 2018
by
anonymous
Last Answer : Locked rotor current of a shaded pole motor is slightly more than full load current.
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85 views
1 answer
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Mar 20, 2018
by
anonymous
Last Answer : The rotor of a hysteresis motor is made of chrome steel.
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56 views
1 answer
asked
Mar 20, 2018
by
anonymous
Last Answer : In a hysteresis motor, the rotor must have retentivity.
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74 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : The rotor developed by a single-phase motor at starting is zero.
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1 answer
asked
Mar 20, 2018
by
anonymous
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An electric motor in which both stator field and rotor rotates with same speed is called?
Last Answer : An electric motor in which both stator field and rotor rotates with same speed is called synchronous motor.
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181 views
1 answer
asked
Mar 18, 2018
by
anonymous
The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?
Last Answer : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.
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303 views
1 answer
asked
Mar 20, 2018
by
anonymous
In dc machines, the armature windings are placed on the rotor because of the necessity for (1) electromechanical energy conversion (2) generation of voltage (3) commutation (4) development of torque
Last Answer : 3 Commutation
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294 views
2 answers
asked
May 1, 2018
by
anonymous
Last Answer : The bearings used to support the rotor shafts are generally ball bearings.
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122 views
1 answer
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Mar 20, 2018
by
anonymous
Salient pole rotor is use for which speed?
Last Answer : Salient pole rotor is use for low and medium speed prime movers.
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100 views
1 answer
asked
Mar 18, 2018
by
anonymous
Which rotor is use for high speed in turbo alternators?
Last Answer : Non-salient pole rotor is used for high speed in turbo alternators.
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82 views
1 answer
asked
Mar 18, 2018
by
anonymous
In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then (A) the flux is constant (B) the flux first decreases and then increases in ... increases and decreases in the opposite direction with the same magnitude (D) current flows through the rotor
Last Answer : In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then the flux first decreases and then increases in the same direction
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95 views
1 answer
asked
Apr 28, 2018
by
anonymous
A 3-phase, 4-pole, 50Hz induction motor runs at a speed of 1440 rpm. The rotating field produced by the rotor rotates at a speed of ________ rpm with respect to stator field. (A) 1500 (B) 0 (C) 1440 (D) 60
Last Answer : 0
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2.1k views
2 answers
asked
Apr 28, 2018
by
anonymous
An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is (A) 5.06 kW (B) 0.3 kW (C) 100 kW (D) 83.33 kW
Last Answer : An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is 83.33 kW
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179 views
1 answer
asked
Apr 28, 2018
by
anonymous
Last Answer : The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it helps in reducing the tendency of the rotor teeth to remain under the stator teeth.
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146 views
1 answer
asked
Mar 20, 2018
by
anonymous
The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as?
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106 views
0 answers
asked
Mar 20, 2018
by
anonymous
number of windings of a coil in a stator of ac motor for ey slot ac motor
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134 views
0 answers
What is a stator in a motor?
Last Answer : Stator is the stationary part of the electrical machine both motor and generator. In motor it provide the rotating magnetic field to drive rotor and in case of generator stator convert rotating magnetic field into current.
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91 views
1 answer
asked
Dec 16, 2017
by
anonymous
Which type of motor would you recommend for using in a steel mill and on an electric vehicle? Explain your answer
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2 views
0 answers
Mc Master Motor
Last Answer : The McMaster motor is based on the principle of the rotary engine. The McMaster motor is the centerpiece of a totally new way of looking at motorized transportation which involves the ... McMaster motor will be considerably cheaper to operate once its unique fuel sources are commercially developed.
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1 answer
DC MOTOR MCQ
Last Answer : 101. Which of the following loss in a D.C. generator is dissipated in the form of heat? (a) Mechanical loss (b) Core loss (c) Copper loss (d) All of the above Ans: d 102. Which of the following ... (b) does not run as a generator (c) also runs as a motor comes to stop after sometime Ans: a
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480 views
3 answers
What is the purpose of Overload Protection in a motor circuit?
Last Answer : Ans. The Overload Protection is used in a motor circuit to protect it from sustained over currents.
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54 views
1 answer
What is a motor?
Last Answer : Ans. Motor is a machine which converts electrical energy into mechanical energy.
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1 answer
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What is Motor Brake ?
Last Answer : The most commonly used brakes are friction brakes. They work on the principle that friction can be used in converting the mechanical energy of an object in motion into heat energy. This ... with an electronic motor brakes. These brakes are also suitable for power-generating machines like windmills.
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1 answer
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Write the steps to rewind an electric motor
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MCQ on Motor Control Center
Last Answer : 1. MCC stands for ______ a. Motor Control Center b. Motor Control Cost c. Machine Components Center d. None of the above Answer : a. Motor Control Center 2. MCC contains _____ a. Fuse b. MCB c. ... a) Start the motor b) Accelerate the motor c) Decelerate the motor d) Stop the motor Answer : a
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242 views
1 answer
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Explain how cooling is achieved in pipe ventilated type during motor enclosures
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asked
May 24, 2021
by
izoh
Basic electrical engineering
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0 answers
Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.
Last Answer : Necessity of Starter for D.C. Motor: Armature current is given by equation Ia = (V−Eb)/Ra i) If the motor is at standstill or rest, back emf Eb is zero (as Eb= ZNP/(60A), at start speed N ... . Types of D.C. motor starters: i) Two point starter ii)Three point starter iii) Four point starter
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318 views
1 answer
asked
May 22, 2020
by
anonymous
State at least one function and the material used for the following parts of DC Motor.
Last Answer : Part Function Material Yoke -Provides mechanical support for poles -Acts as protecting cover for machine -Provides path for magnetic flux Cast Iron OR Cast Steel Field Winding - ... Pole core Provides mechanical support to field winding. Cast Iron OR Cast Steel
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161 views
1 answer
asked
May 22, 2020
by
anonymous
Explain the working principle of induction motor.
Last Answer : Working principle of induction motor: * When the motor is excited with three-phase supply, three-phase stator winding carries three-phase currents & produces a rotating magnetic field of constant magnitude and ... , which tend to move the rotor in the same direction as the rotating magnetic field.
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598 views
1 answer
asked
May 22, 2020
by
anonymous
State the insulating materials used in motor. Write temperature class and withstand temperature ranges for them.
Last Answer : The insulating materials used in motor are as belows: 1. Cotton, 2. Silk, or paper, 3. Press board, 4. Resins 5. PVC 6. Cellulose-Fiber, 7. Enameled coating, etc ... Over 180° Mica, porcelain, ceramics, glass quartz, asbestos, treated glass fiber or treated asbestos. etc.
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177 views
1 answer
asked
May 7, 2020
by
anonymous
List different starting methods of three phase synchronous motor. Explain any one of them.
Last Answer : Different Starting Methods of Three Phase Synchronous Motor: As synchronous motor is not self starting, different methods of starting are as follows: 1) By using an Induction (Pony) motor 2) ... . The rotor gets pulled into synchronism and starts running at constant speed as a synchronous motor.
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163 views
1 answer
asked
May 7, 2020
by
anonymous
Draw and explain V and inverted V curves for synchronous motor.
Last Answer : V curves' and inverted V curves' for Synchronous Motor: V curve: V curve is a plot of the stator current versus field current for different constant loads. The graph is plotted ... Vcurves of synchronous motor. The highest point on each of these curves indicates unity power factor.
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500 views
1 answer
asked
May 7, 2020
by
anonymous
State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.
Last Answer : Modifications are necessary in a dc series motor so that it operates satisfactorily on ac supply. The modifications are as follows: 1) AC series motor is built with a few field turns as ... and grinders 5) High speed vacuum cleaners 6) Sewing machines 7) Food processors 8) Drilling machine
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384 views
1 answer
asked
May 7, 2020
by
anonymous
Explain the activities carried out during weekly maintenance of 3 ph. Induction motor.
Last Answer : Activities Carried out During Weekly Maintenance of 3 ph. Induction Motor: 1) Check belt tension. In cases where this is excessive it should immediately be reduces and in the case of sleeve ... and cooled by oil mist systems its important to check the oil mist flow paths/pressure components.
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163 views
1 answer
asked
May 7, 2020
by
anonymous
Describe with neat sketch working of hysteresis motor.
Last Answer : Working: When stator is energized with single phase ac supply, rotating magnetic field is produced because of starting (auxiliary) and main windings, which remain in circuit permanently. The ... the principle of magnetic locking this motor either rotates at synchronous speed or not at all.
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206 views
1 answer
asked
May 7, 2020
by
anonymous
List applications of stepper motor.
Last Answer : Applications of Stepper Motor: 1) Computer controlled systems 2) Numerical control of machine tools 3) Tape drives 4) Floppy disc drives 5) Computer printers 6) X-Y plotters 7) ... ) Extruders 21) Engravers 22) Analytical and Medical instruments 23) Embroidery Machines 24) Packaging Machines
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153 views
1 answer
asked
May 7, 2020
by
anonymous
List different torques in synchronous motor.
Last Answer : Different Torques in Synchronous Motor: 1) Starting torque 2) Running torque 3) Pull-in torque 4) Pull-out torque
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116 views
1 answer
asked
May 7, 2020
by
anonymous
State suitable single phase motor for following applications: (i) Table fan (ii) Mixers and Grinders
Last Answer : Application Suitable Single Phase Motor Table Fan 1) Capacitor split phase motor 2) Capacitor start capacitor run motor Mixers and Grinders 1) Universal motor 2) A.C. Series motor
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98 views
1 answer
asked
May 7, 2020
by
anonymous
State the function of following parts in Induction motor. (i) Stator (ii) Slip rings
Last Answer : Name of part Function Stator 1) Stator frame supports the core, terminal box and protects the inner parts. 2) Stator core houses stator winding. 3) Stator winding ... ) Provides facility to connect external resistance to rotor circuit through brushes for starting and control.
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223 views
1 answer
asked
May 7, 2020
by
anonymous
List the energy conservation technique in induction motor.
Last Answer : Following are the list of energy conservation techniques in electrical motors: 1) Reduction in iron losses by using low loss silicon steel core material laminated to thinner dimension. 2) Using bigger length ... at light load. 13) By rewinding in induction motor 14) By motor survey
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1.1k views
1 answer
asked
May 3, 2020
by
anonymous
With a neat sketch give the working of shaded pole induction motor.
Last Answer : Explanation: It has squirrel cage rotor and salient pole stator. The stator poles are shaded partially by short circuited conductor band to create the phase difference between the fluxes emerging from shaded ... rotating magnetic field in the air-gap and torque is exerted on the squirrel cage rotor.
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266 views
2 answers
asked
Apr 27, 2020
by
anonymous
List the main parts of D.C. motor
Last Answer : Main parts of D.C. motor and their functions: Part Functions Yoke i) Provides mechanical support for poles. ii) Acts as protecting cover for machine. iii) Carries magnetic flux. ... a fixed physical position relative to the stator. Shaft Used to transfer mechanical power
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153 views
1 answer
asked
Apr 27, 2020
by
anonymous
List different types of stepper motor. State one application of stepper motor.
Last Answer : Types of stepper motor : (i)Variable - reluctance motor (ii) Permanent- magnet motors (iii) Hybrid motors. Applications of stepper motor : In robotics, In CNC machines, In computers, printers, ... In Watches, In biomedical applications such as X-ray machines, CT scan, In Process control systems.
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93 views
1 answer
asked
Apr 27, 2020
by
anonymous
Write two applications of D.C. series motor.
Last Answer : The applications of D.C. series motor: 1. Cranes 2. Hoists 3. Trolley and cars 4. Conveyors 5. For traction work i.e. electric locomotives 6. Elevator 7. Air compressor
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122 views
1 answer
asked
Apr 27, 2020
by
anonymous
State the principle of operation of d.c. motor.
Last Answer : When a current carrying conductor is placed in a magnetic field, the conductor experiences the force. The magnitude of force is given by F = BIL newton where F – Force B – maximum flux density I – Current L – Length of conductor
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147 views
1 answer
asked
Apr 27, 2020
by
anonymous
DC motor gross torque example
Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
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145 views
2 answers
asked
Apr 24, 2020
by
anonymous
