Which D.C. motor has got maximum self relieving property ?

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1 Answer

Answer :

Series motor has got maximum self relieving property.

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The condition for maximum power in case of D.C. motor is?

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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.

Which D.C. motor has got maximum self loading property?

Last Answer : Differentially compounded D.C. motor has got maximum self loading property.

A synchronous motor can be made self starting by providing?

Description : A synchronous motor can be made self starting by providing?

Last Answer : A synchronous motor can be made self-starting by providing damper bar.

How is a three phase cage induction motor self starting?

Description : How is a three phase cage induction motor self starting?

Last Answer : Any type of induction motor is self starting. Because the reason for torqe production require two flux displaced by some angle theta.If theta is constant with time then torqe will be constant;if ... torqe also pulsating. In induction motor this angle theta is not pulsating.so it is self starting 

Is induction motor is self starting?

Description : Is induction motor is self starting?

Last Answer : Single phase induction motor is not self starting. Three phase induction motor is self starting.

The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and

Description : The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is (A) 0.25 pu (B) 0.5 pu (C) 1.0 pu (D) 1.5 pu

Last Answer : The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is 0.5 pu

The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is?

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.

In repulsion motor, maximum torque is developed when?

Last Answer : In repulsion motor, maximum torque is developed when brush axis is at 45° electrical to the field axis.

The maximum constant load torque under which a synchronous motor will pull into synchronism...

Description : 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.

What is the maximum value of torque angle in synchronous motor?

Description : What is the maximum value of torque angle in synchronous motor?

Last Answer : The maximum value of torque angle in synchronous motor is 90 degrees electrical.

The synchronous motor will develop maximum power when the load angle is?

Description : The synchronous motor will develop maximum power when the load angle is?

Last Answer : The synchronous motor will develop maximum power when the load angle is 900.

Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.

Description : Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter. 

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State at least one function and the material used for the following parts of DC Motor.

Description : State at least one function and the material used for the following parts of DC Motor.

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

Description : 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.

A d.c. motor can be looked upon as d.c. generator with the power flow?

Description : A d.c. motor can be looked upon as d.c. generator with the power flow?

Last Answer : A d.c. motor can be looked upon as d.c. generator with the power flow reversed.

The Eb/V ratio of a d.c. motor is an indication of its?

Description : The Eb/V ratio of a d.c. motor is an indication of its?

Last Answer : The Eb/V ratio of a d.c. motor is an indication of its efficiency.

The normal value of the armature resistance of a d.c. motor is?

Description : The normal value of the armature resistance of a d.c. motor is?

Last Answer : The normal value of the armature resistance of a d.c. motor is 0.5.

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

Description : 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.

In a d.c. motor, unidirectional torque is produced with the help of?

Description : In a d.c. motor, unidirectional torque is produced with the help of

Last Answer : Commutator provides unidirectional torque and pulsating dc

In DC motor iron losses are occurred in?

Description : In DC motor iron losses are occurred in?

Last Answer : In DC motor iron losses are occurred in the armature.

D.C. motor is to a drive a load which is almost nil for certain part of the load cycle...

Description : D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select the?

Last Answer : D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select the compound motor.

D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value...

Description : D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the?

Last Answer : DC motor mostly preferred is DC series motor becaus the load is continuous for a long time

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.

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.

For which types of D.C. motor, dynamic braking is generally used ?

Last Answer : Shunt motors,  Series motors, Compound motors

Torque developed by a D.C. motor depends upon?

Last Answer : Torque developed by a D.C. motor depends upon magnetic field, active length of the conductor, current flow through the conductors, number of conductors, radius of armature.

If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will?

Last Answer : If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will increase.

State maximum power transfer theorem for DC circuit.

Description : State maximum power transfer theorem for DC circuit.

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D.C. generators are normally designed for maximum efficiency around?

Last Answer : D.C. generators are normally designed for maximum efficiency around full-load.

The condition for maximum efficiency for a D.C. generator is?

Last Answer : The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.

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Description : Self Aquired Vs Ancestoral Property?

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In case the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be?

Last Answer : In case the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be less than 50%.

The maximum torque of d.c. motors is limited by?

Description : The maximum torque of d.c. motors is limited by?

Last Answer : The maximum torque of d.c. motors is limited by commutation.

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

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What would happen if a DC motor was supplied with AC ?

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State the function of following parts of DC motor : i) Yoke ii) Poles iii) Field winding iv) Commutator.

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Description : State any four applications of DC shunt motor.

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Describe the reason of using dc series motor for electric trains.

Description : Describe the reason of using dc series motor for electric trains.

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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.

Description : 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

A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance

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In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at

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The function of a brush and commutator arrangement in a dc motor is to

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Last Answer : The function of a brush and commutator arrangement in a dc motor is to produce unidirectional torque