In case of D.C. shunt motors the speed is dependent on back e.m.f. only because?

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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asked May 8, 2018 by anonymous

The speed of a D.C. shunt motor can be increased by?

Last Answer : The speed of a D.C. shunt motor can be increased by increasing the resistance in field circuit.

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asked Mar 20, 2018 by anonymous

As the load is increased the speed of D.C. shunt motor will?

Last Answer : As the load is increased the speed of D.C. shunt motor will reduce slightly.

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asked Mar 20, 2018 by anonymous

In a D.C. shunt motor, speed is?

Last Answer : In a D.C. shunt motor, speed is independent of armature current.

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asked Mar 20, 2018 by anonymous

When two D.C. series motors are connected in parallel, the resultant speed is?

Last Answer : When two D.C. series motors are connected in parallel, the resultant speed is normal speed.

378 views 1 answer

asked Mar 20, 2018 by anonymous

Why does the speed of a DC shunt motor decrease as the load increases?

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.

2.7k views 1 answer

asked Jul 5, 2019 by anonymous

What is the back EMF of a dc motor?

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asked Mar 15, 2018 by anonymous

The speed of a D.C. shunt motor more than its full-load speed can be obtained by?

Last Answer : The speed of a D.C. shunt motor more than its full-load speed can be obtained by decreasing the field current.

146 views 1 answer

asked Mar 20, 2018 by anonymous

In case of conductively compensated D.C. series motors, the compensating winding is provided?

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.

97 views 1 answer

asked Mar 20, 2018 by anonymous

Starters are used with D.C. motors because?

Last Answer : Starters are used with D.C. motors because to restrict armature current as there is no back e.m.f. while starting.

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

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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asked May 3, 2018 by anonymous

For a D.C. shunt motor if the excitation is changed?

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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asked Mar 20, 2018 by anonymous

The armature torque of the D.C. shunt motor is proportional to?

Last Answer : The armature torque of the D.C. shunt motor is proportional to armature current.

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asked Mar 20, 2018 by anonymous

In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be?

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.

366 views 1 answer

asked Mar 20, 2018 by anonymous

If the field of a D.C. shunt motor gets opened while motor is running?

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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asked Mar 20, 2018 by anonymous

Differentially compound D.C. motors can find applications requiring?

Last Answer : Differentially compound D.C. motors can find applications requiring low starting torque.

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asked Mar 20, 2018 by anonymous

What is back emf?

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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asked Apr 27, 2020 by anonymous

The back emf of synchronous motor depends on?

The back emf of synchronous motor depends on?
Last Answer : The back emf of synchronous motor depends on load angle.

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asked Mar 18, 2018 by anonymous

What is back EMF of synchronous motor?

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asked Mar 15, 2018 by anonymous

What is back EMF in inductor?

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asked Mar 15, 2018 by anonymous

What is the back EMF in Transformers?

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asked Mar 15, 2018 by anonymous

What is the back EMF of the motor?

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asked Mar 15, 2018 by anonymous

What is the back EMF?

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.

107 views 1 answer

asked Mar 15, 2018 by anonymous

If field current is decreased in shunt dc motor, the speed of the motor

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

2.8k views 4 answers

asked Aug 25, 2019 by anonymous

The counter e.m.f. of a d.c. motor?

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.

90 views 1 answer

asked Mar 26, 2018 by anonymous

When the armature of a D.C. motor rotates, e.m.f. induced is

Last Answer : When the armature of a D.C. motor rotates, e.m.f. induced is back e.m.f.

203 views 1 answer

asked Mar 20, 2018 by anonymous

The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors

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

370 views 1 answer

asked Apr 29, 2018 by anonymous

DC shunt motor

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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asked Apr 23, 2020 by anonymous

State any four applications of DC shunt motor.

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

115 views 2 answers

asked Jul 27, 2019 by anonymous

If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens?

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.

158 views 1 answer

asked Mar 20, 2018 by anonymous

The purpose of retardation test on D.C. shunt machines is to find out?

Last Answer : The purpose of retardation test on D.C. shunt machines is to find out stray losses.

74 views 1 answer

asked Mar 20, 2018 by anonymous

Why are DC motors used in trains and not AC motors ?

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.

160 views 1 answer

asked Sep 3, 2019 by anonymous

Which of the following motors can run on both AC and DC?

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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asked Apr 29, 2018 by anonymous

During rheostat braking of D.C. series motors?

Last Answer : During rheostat braking of D.C. series motors motor is run as a generator.

85 views 1 answer

asked Mar 20, 2018 by anonymous

Why are the D.C. motors preferred for traction applications?

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.

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

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.

355 views 2 answers

asked May 1, 2018 by anonymous

The speed of a D.C. motor can be controlled by varying

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

388 views 1 answer

asked Mar 20, 2018 by anonymous

The speed of a D.C. series motor is?

Last Answer : The speed of a D.C. series motor is inversely proportional to the armature current.

114 views 1 answer

asked Mar 20, 2018 by anonymous

What are the speed control methods of dc motor?

What are the speed control methods of dc motor?
Last Answer : Field control of DC motor Armature control of DC motor

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...

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

1.8k views 2 answers

asked Mar 21, 2018 by anonymous

In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will?

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.

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...

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.

668 views 1 answer

asked Mar 21, 2018 by anonymous

Damper winding is provided in 3 phase synchronous motors to :

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

93 views 1 answer

asked Apr 29, 2018 by anonymous

Stepper motors are used in

Stepper motors are used in (1) printers (2) lifts (3) amplifiers (4) oscillators
Last Answer : Stepper motors are used in printers

68 views 1 answer

asked Apr 29, 2018 by anonymous

anonymous · Answer 1 · 2018-03-20T20:13:48+0000

In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.

In case of D.C. shunt motors the speed is dependent on back e.m.f. only because?

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