Last Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.
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324 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : In D.C. shunt motors as load is reduced the speed will remain almost constant.
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145 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.
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423 views
1 answer
asked
Mar 20, 2018
by
anonymous

Do AC induction motors have back EMF?
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71 views
0 answers
asked
Mar 15, 2018
by
anonymous

Last Answer : If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will increase.
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201 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : D.C. shunt motors are used for driving machine tools.
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85 views
1 answer
asked
Mar 20, 2018
by
anonymous

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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481 views
1 answer
asked
May 8, 2018
by
anonymous
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Last Answer : The speed of a D.C. shunt motor can be increased by increasing the resistance in field circuit.
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134 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : As the load is increased the speed of D.C. shunt motor will reduce slightly.
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142 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a D.C. shunt motor, speed is independent of armature current.
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87 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : When two D.C. series motors are connected in parallel, the resultant speed is normal speed.
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378 views
1 answer
asked
Mar 20, 2018
by
anonymous

Why does the speed of a DC shunt motor decrease as the load increases?
Last Answer : Because if the load is increasing then the torque must also be increase. If not then the speed of motor will decrease.
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2.7k views
1 answer
asked
Jul 5, 2019
by
anonymous

What is the back EMF of a dc motor?
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2.6k views
0 answers
asked
Mar 15, 2018
by
anonymous

Last Answer : The speed of a D.C. shunt motor more than its full-load speed can be obtained by decreasing the field current.
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146 views
1 answer
asked
Mar 20, 2018
by
anonymous

In case of conductively compensated D.C. series motors, the compensating winding is provided?
Last Answer : In case of conductively compensated D.C. series motors, the compensating winding is provided in series with armature winding.
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97 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Starters are used with D.C. motors because to restrict armature current as there is no back e.m.f. while starting.
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119 views
1 answer
asked
Mar 20, 2018
by
anonymous

A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is
Last Answer : A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is 36 Ohm
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329 views
1 answer
asked
May 3, 2018
by
anonymous

Last Answer : For a D.C. shunt motor if the excitation is changed torque will change but power will remain constant.
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168 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The armature torque of the D.C. shunt motor is proportional to armature current.
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210 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be more than full-load current.
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366 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : If the field of a D.C. shunt motor gets opened while motor is running the motor will attain dangerously high speed.
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135 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Differentially compound D.C. motors can find applications requiring low starting torque.
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125 views
1 answer
asked
Mar 20, 2018
by
anonymous

What is back emf?
Last Answer : Back EMF: When a current carrying conductor is placed in a magnetic field it experiences a force; when it moves due to the force it (conductor) cuts the magnetic field due to which an emf is ... (hence the applied armature voltage) is opposed by the induced emf which is therefore called as Back emf.
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91 views
1 answer
asked
Apr 27, 2020
by
anonymous

The back emf of synchronous motor depends on?
Last Answer : The back emf of synchronous motor depends on load angle.
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65 views
1 answer
asked
Mar 18, 2018
by
anonymous

What is back EMF of synchronous motor?
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77 views
0 answers
asked
Mar 15, 2018
by
anonymous

What is back EMF in inductor?
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138 views
0 answers
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Mar 15, 2018
by
anonymous

What is the back EMF in Transformers?
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77 views
0 answers
asked
Mar 15, 2018
by
anonymous

What is the back EMF of the motor?
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68 views
0 answers
asked
Mar 15, 2018
by
anonymous

What is the back EMF?
Last Answer : When the armature of a d.c. motor rotates under the influence of the driving torque, the armature conductors move through the magnetic field and hence e.m.f. is induced in them as in a generator. The ... that energy conversion in a d.c. motor is only possible due to the production of back emf.
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107 views
1 answer
asked
Mar 15, 2018
by
anonymous

If field current is decreased in shunt dc motor, the speed of the motor (a) remains same. (b) increases. (c) decreases. (d) none of the above.
Last Answer : increases
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2.8k views
4 answers
asked
Aug 25, 2019
by
anonymous

The counter e.m.f. of a d.c. motor?
Last Answer : The counter e.m.f. of a d.c. motor helps in energy conversion.
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90 views
1 answer
asked
Mar 26, 2018
by
anonymous

Last Answer : When the armature of a D.C. motor rotates, e.m.f. induced is back e.m.f.
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203 views
1 answer
asked
Mar 20, 2018
by
anonymous
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The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is (1) 1000V (2) 100V (3) 600V (4) 10,000V
Last Answer : The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is 1000V
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370 views
1 answer
asked
Apr 29, 2018
by
anonymous

DC shunt motor
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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140 views
2 answers
asked
Apr 23, 2020
by
anonymous

State any four applications of DC shunt motor.
Last Answer : Applications of DC shunt motor: 1) Lathe machines 2) drilling machines 3) milling machines 4) Printing machinery 5) Paper industry 6) centrifugal and reciprocating pumps 7) blowers 8)fans
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115 views
2 answers
asked
Jul 27, 2019
by
anonymous

Last Answer : If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens this will make armature to take heavy current, possibly burning it.
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158 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The purpose of retardation test on D.C. shunt machines is to find out stray losses.
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74 views
1 answer
asked
Mar 20, 2018
by
anonymous

Why are DC motors used in trains and not AC motors ?
Last Answer : The reason is torque. torque is inversely proportional to speed..i.e when th knowe train comes to rest position to motion.. initial speed is zero..so it requires high starting torque for ... current will flow through field and armature coils then maximum torque is available at the intial condition.
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160 views
1 answer
asked
Sep 3, 2019
by
anonymous

Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
Last Answer : Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
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179 views
1 answer
asked
Apr 29, 2018
by
anonymous

Last Answer : During rheostat braking of D.C. series motors motor is run as a generator.
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85 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : The D.C. motors preferred for traction applications beacuse the speed is inversely proportional to the torque and the torque is proportional to square of armature current.
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159 views
1 answer
asked
Mar 20, 2018
by
anonymous

The fall in speed of a dc generator due to increase in load can be corrected by (1) cooling the armature.. (2) increasing the excitation. (3) reducing the load voltage. (4) increasing the input to the prime mover
Last Answer : It can be corrected by increasing the input to the prime mover.
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355 views
2 answers
asked
May 1, 2018
by
anonymous

The speed of a D.C. motor can be controlled by varying 1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above
Last Answer : The speed of a D.C. motor can be controlled by varying 1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above
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388 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The speed of a D.C. series motor is inversely proportional to the armature current.
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114 views
1 answer
asked
Mar 20, 2018
by
anonymous

What are the speed control methods of dc motor?
Last Answer : Field control of DC motor Armature control of DC motor
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252 views
2 answers
asked
Dec 16, 2017
by
anonymous

A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly?
Last Answer : 200V/E2 = 1000/1200 E2= 240 V
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1.8k views
2 answers
asked
Mar 21, 2018
by
anonymous

Last Answer : In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will remain unchanged.
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228 views
1 answer
asked
Mar 20, 2018
by
anonymous

The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be?
Last Answer : The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be 580 V.
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668 views
1 answer
asked
Mar 21, 2018
by
anonymous

Damper winding is provided in 3 phase synchronous motors to :
Last Answer : Damper winding is provided in 3 phase synchronous motors to : provide starting torque and prevent hunting
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93 views
1 answer
asked
Apr 29, 2018
by
anonymous

Stepper motors are used in (1) printers (2) lifts (3) amplifiers (4) oscillators
Last Answer : Stepper motors are used in printers
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68 views
1 answer
asked
Apr 29, 2018
by
anonymous
