Last Answer : In a hysteresis motor, the rotor must have retentivity.
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73 views
1 answer
asked
Mar 20, 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
asked
Mar 20, 2018
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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205 views
1 answer
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May 7, 2020
by
anonymous
Last Answer : A hysteresis motor works on the principle of hysteresis loss.
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121 views
1 answer
asked
Mar 20, 2018
by
anonymous
Last Answer : The direction of rotation of an hysteresis motor is determined by position of shaded pole with respect to main pole.
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230 views
1 answer
asked
Mar 20, 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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132 views
0 answers
asked
Apr 16, 2020
by
anonymous
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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165 views
1 answer
asked
May 3, 2018
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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582 views
2 answers
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Apr 28, 2018
by
anonymous
Last Answer : The rotor developed by a single-phase motor at starting is zero.
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90 views
1 answer
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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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177 views
1 answer
asked
Mar 18, 2018
by
anonymous
What is the rotor of a motor?
Last Answer : Rotor is the rotating or moving part in motor and generator.
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133 views
1 answer
asked
Dec 16, 2017
by
anonymous
A synchronous motor can be made self starting by providing?
Last Answer : A synchronous motor can be made self-starting by providing damper bar.
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131 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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302 views
1 answer
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Mar 20, 2018
by
anonymous
Last Answer : As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for sound equipment.
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115 views
1 answer
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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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292 views
2 answers
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May 1, 2018
by
anonymous
What is magnetic hysteresis? What is the cause of hysteresis?
Last Answer : Magnetic hysteresis: When a magnetic material is subjected to cycle of magnetization, it is found that flux density (B) in the material lags behind applied magnetizing force (H). This ... the movement of orientation, due to which the flux density lags behind the magnetic field intensity.
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77 views
1 answer
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Sep 4, 2018
by
anonymous
State the factors affecting hysteresis loss.
Last Answer : i) Flux density ii) Frequency iii) Volume of the magnetic material iv) Nature of magnetic material
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86 views
1 answer
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Sep 4, 2018
by
anonymous
Explain the hysteresis loop of a magnetic material with neat diagram.
Last Answer : Hysteresis loop of magnetic material: The circuit arrangement for plotting the hysteresis loop is shown in figure given below. The electromagnetic part consists of a coil wound on the iron ring ... one magnetic reversal is called hysteresis loop. Meaning of hysteresis is to lag behind.
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662 views
1 answer
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Aug 8, 2018
by
anonymous
Hysteresis is commonly found in ______ A) ferromagnetic materials B) ferroelectric materials C) both A and B D) none of these
Last Answer : Hysteresis is commonly found in ______ A) ferromagnetic materials B) ferroelectric materials C) both A and B D) none of these
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125 views
1 answer
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Apr 29, 2018
by
anonymous
The term hysteresis is associated with (A) On-Off control (B) P-I control (C) Feed forward control (D) Ratio control
Last Answer : The term hysteresis is associated with On-Off control
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74 views
1 answer
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Apr 26, 2018
by
anonymous
If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be?
Last Answer : If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be large.
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623 views
1 answer
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Mar 25, 2018
by
anonymous
In a magnetic material hysteresis loss takes place primarily due to?
Last Answer : In a magnetic material hysteresis loss takes place primarily due to it high retentivity.
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410 views
1 answer
asked
Mar 25, 2018
by
anonymous
What is the difference between eddy current and hysteresis loss?
Last Answer : Loss occurred by magnetising and demagnetising process is called histerisis loss and the current flowed due to the magnetic field produced by the electric field applied is called eddy current losses
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3.0k views
1 answer
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Mar 15, 2018
by
anonymous
Explain hysteresis loss, eddy current loss and skin effect limitations with reference to magnetic material.
Last Answer : Hysteresis loss: Hysteresis loss is a loss which occurs due to the friction of magnetic domain due to the change in magnetic field in ferromagnetic material like iron. Hysteresis loss causes power loss ... loss in transformer is given by, We=Kef2Kf2Bm2watts Skin effect limitations:
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721 views
1 answer
asked
Feb 16, 2018
by
anonymous
Brushes of DC machine are made up of ?
Last Answer : Brushes of DC machine are made up of carbon.
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165 views
1 answer
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Mar 3, 2018
by
anonymous
From which material field coils of DC generator are made of?
Last Answer : Field coils of DC generator are usually made of copper.
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118 views
1 answer
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Mar 3, 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
asked
Mar 20, 2018
by
anonymous
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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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81 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
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Mar 20, 2018
by
anonymous
How To Make Chalking Made Easy
Last Answer : Chalking Made Easy: Simple Instructions for Scrapbookers and Card Designers Chalking is a quick, inexpensive way to add creativity, color, and character to your scrapbooking layouts and other papercrafts. With a ... to experiment. This is where the artist in you is allowed to come out and play!
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5 views
1 answer
How Wool is Made
Last Answer : How Wool is Made Wool is the fiber derived from the fleece or the fur of the Caprinae family. This family consists of chamois, goats, serows, sheep and relatives. Wool may is made from ... the final wool fabric. These finishing procedures will determine the warmth, durability and value of the wool.
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5 views
1 answer
How Silk is Made
Last Answer : How Silk is Made Silk is made from the fine woven filaments of cocoons of silkworms. There are almost 70 species of silk moths. The most famous is the Bombyx mori. The caterpillar is among ... of each filament, the way each filament is looped and twisted into the silk thread are also considere
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14 views
1 answer
How Paper is Made
Last Answer : How Paper is Made Paper is an essential commodity utilized for business and education. Paper is typically made from plant fibres. Most common would be from the fibres of trees. Other materials such as ... done to sift all the unneeded particles of the wood. The cellulose fibres will remain intact.
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4 views
1 answer
How Is Glass Made?
Last Answer : How Is Glass Made? Glass is a common household object. It is an amorphous noncrystalline solid that has several applications in our daily lives. Glass is transparent to visible light. This makes it ... filler for rubbers and plastics. It is also used in many coating adhesives, cements, and sealants.
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12 views
1 answer
How are Paintballs Made
Last Answer : How are Paintballs Made What is a Paintball? Paintball is a sport in which the aim of the participants is to eliminate people on the other team by shooting at them paintballs. These so-called paintballs ... as soon as the balls have dried up. When ready, the paintballs are packed and moved onwards.
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4 views
1 answer
How are Jigsaw Puzzles Made
Last Answer : How are Jigsaw Puzzles Made What is a jigsaw puzzle? A jigsaw puzzle can be described as a puzzle made up of small tiles of different shapes that can interlock with one another. Each of these tiles has ... ready. You can ask anyone to look at the uncut picture and assemble the pieces with its help.
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3 views
1 answer
asked
May 15, 2021
by
anonymous
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How are Diamonds Made
Last Answer : How are Diamonds Made What is a Diamond? Diamonds are typically formed deep beneath the earth's surface. They are made up of pure carbon which has been placed under immense pressure for millions of years ... , diamonds can be made to grow up to 10 millimeters across and 4.5 millimeters in thickness.
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6 views
1 answer
asked
May 10, 2021
by
anonymous
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How Electricity is Made ?
Last Answer : How Electricity is Made Electricity is produced when the balance between the protons and electrons of an atom is disrupted by a certain force. It transmits an electrical charge through solid matter. ... as the classic Dutch six-bladed wind mills. These wind mills were used in ancient times.
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7 views
1 answer
asked
May 9, 2021
by
anonymous
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The IC chips, used in computers, is made of (1) Iron oxide (2) Silicon (3) Graphite (4) Silica
Last Answer : 2 These are made on silicon wafers which is aa semi conductor. ...
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120 views
2 answers
asked
May 1, 2018
by
anonymous
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A switch tail ring counter is made by using a single D-FF. The resulting circuit is (A) T-FF (B) D-FF (C) SR-FF (D) JK-FF
Last Answer : A switch tail ring counter is made by using a single D-FF. The resulting circuit is T-FF
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186 views
1 answer
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Apr 28, 2018
by
anonymous
Last Answer : Standard resistor is made from maganin.
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57 views
1 answer
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Mar 21, 2018
by
anonymous
D.C. shunt relays are made of?
Last Answer : D.C. shunt relays are made of many turns of thin wire.
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2.7k views
1 answer
asked
Mar 19, 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
Split phase induction motor
Last Answer : Split phase induction motor : There are two windings used in split phase induction motor. It is a type of single-phase induction motor. There are two winding one is called main winding and ... motor have low starting torque it is used for small fans, blowers, centrifugal pumps, grinders etc.
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230 views
1 answer
asked
Sep 20, 2018
by
anonymous
Describe the reason of using dc series motor for electric trains.
Last Answer : Electric trains require an inverse torque speed characteristics for proper operation. That is a higher torque is required at start (when speed is nil or low) and as the train picks up ... torque - speed characteristics of DC series motors match, these motors are suitable for electric trains
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142 views
1 answer
asked
Sep 18, 2018
by
anonymous
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A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be
Last Answer : A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be 474 V
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483 views
1 answer
asked
May 8, 2018
by
anonymous
