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

by

1 Answer

Answer :

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

by

Related questions

Satisfactory commutation of D.C. machines requires?

Last Answer : Satisfactory commutation of D.C. machines requires brushes should be of proper grade and size, brushes should smoothly run in the holders, smooth, concentric commutator properly undercut.

Brushes of D.C. machines are made of?

Last Answer : Brushes of D.C. machines are made of carbon.

Hopkinson's test on D.C. machines is conducted at?

Last Answer : Hopkinson's test on D.C. machines is conducted at full-load.

Draw the connection diagram of long shunt differential D.C. compound generator.

Description : Draw the connection diagram of long shunt differential D.C. compound generator.

Last Answer : Ans:

DC shunt motor

Description : 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%; }

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

Description : 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

State any four applications of DC shunt motor.

Description : 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

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 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

Description : 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

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.

D.C. shunt motors are used for driving?

Last Answer : D.C. shunt motors are used for driving machine tools.

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.

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.

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.

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.

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.

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.

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

Last Answer : 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 a D.C. shunt motor, speed is?

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

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.

In D.C. shunt motors as load is reduced?

Last Answer : In D.C. shunt motors as load is reduced the speed will remain almost constant.

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.

In dc machines, the armature windings are placed on the rotor because of the necessity for

Description : 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

In D.C. machines the residual magnetism is of the order of?

Last Answer : In D.C. machines the residual magnetism is of the order of 2 to 3 percent.

In D.C. machines fractional pitch winding is used?

Last Answer : In D.C. machines fractional pitch winding is used to reduce the sparking.

A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave?

Description : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave?

Last Answer : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will be of 5 Hz.

A cumulatively compounded long shunt generator when operating as a motor would be?

Last Answer : A cumulatively compounded long shunt generator when operating as a motor would be differentially compounded long shunt.

The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm...

Description : 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.

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...

Description : 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

For a D.C. machines laboratory following type of D.C. supply will be suitable?

Last Answer : For a D.C. machines laboratory following type of D.C. supply will be suitable induction motor D.C. generator set.

State any two applications of single phase autotransformer.

Description : State any two applications of single phase autotransformer.

Last Answer : Applications of single phase auto transformers: 1) Give small boost to distribution cable to correct the voltage drop. 2) As auto transformer starter for induction motors. 3) As furnace supply ... . 5) In control equipment for single phase locomotives. 6) As dimmer in lighting circuits.

State any two conditions for parallel operation of 3-phase transformer.

Description : State any two conditions for parallel operation of 3-phase transformer.

Last Answer : Conditions for Parallel operation of 3 phase transformer 1) Voltage ratings of both the transformers must be identical. 2) Percentage or p.u. impedance should be equal in magnitude. 3) X/R ratio ... between primary & secondary voltages must be same. 6) Phase sequence on both sides must be same.

Compare core type transformer and shell type transformer on the following parameters. (i) Types of winding used, (ii) Application

Description : Compare core type transformer and shell type transformer on the following parameters. (i) Types of winding used, (ii) Application

Last Answer : Ans:

Define transformation ratio in terms of current and voltage.

Description : Define transformation ratio in terms of current and voltage.

Last Answer : (i) Transformation Ratio (K) is defined as the ratio of the primary current to the secondary current.  (ii) Transformation Ratio (K) is defined as the ratio of the secondary voltage to the primary voltage.

Define: (i) Commercial efficiency of a transformer and (ii) All day efficiency of a transformer.

Description : Define: (i) Commercial efficiency of a transformer and  (ii) All day efficiency of a transformer.

Last Answer : (i) Commercial Efficiency : It is the ratio of output power in watt to the input power in watt. (ii) All day efficiency of a transformer: It is the ratio of output energy in kWh to the input energy in kWh in the 24 hours of the day

A 50 KVA transformer has iron loss 2 kW on full load. Calculate its iron loss at 75% of full load.

Description : A 50 KVA transformer has iron loss 2 kW on full load. Calculate its iron loss at 75% of full load.

Last Answer : Iron loss is dependent on voltage and independent of load. Hence iron loss at 75% of Load = Iron loss at full load = 2 kW

State any four properties of Ideal transformer.

Description : State any four properties of Ideal transformer.

Last Answer : Properties of Ideal transformer: 1) No losses (iron and copper losses), hence no temperature rise. 2) No magnetic leakage i.e (Coefficient of coupling between primary and secondary windings is unity) 3) Zero winding ... drop i.e. E1 = V1, E2 = V2 5) Efficiency 100 %. 6) Regulation 0 %.

State the use of shunt and series resistance used in extension of meter.

Description : State the use of shunt and series resistance used in extension of meter.

Last Answer : Use of shunt and series resistance: i) Use of shunt: To extend the range of Ammeter. ii) Use of series resistance: To extend the range of Voltmeter.

In which of the following transmission lines, the value of the Shunt admittance should be

Description : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

Last Answer : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

Shunt compensation in an EHV line is used to

Description : Shunt compensation in an EHV line is used to (A) Improve stability. (B) Improve the voltage profile. (C) Reduce the fault level. (D) Substitute for synchronous phase modifier.

Last Answer : Shunt compensation in an EHV line is used to Improve the voltage profile.

A shunt fault is characterized by

Description : A shunt fault is characterized by (A) Increase in current, frequency and pf (B) Increase in current, reduction in frequency and pf (C) Increase in current and frequency, reduction in pf (D) Decrease in current and frequency

Last Answer : B

The function of shunt in an ammeter is to?

Last Answer : The function of shunt in an ammeter is to by pass the current.

In a manual shunt motor starter?

Last Answer : In a manual shunt motor starter over load relay is connected in series and no volt relay in parallel with the load.

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.

Shunt capacitance is neglected while considering?

Last Answer : Shunt capacitance is neglected while considering short transmission line.

D.C. shunt relays are made of?

Description : D.C. shunt relays are made of?

Last Answer : D.C. shunt relays are made of many turns of thin wire.

Why shunt capacitor is used?

Description : Why shunt capacitor is used?

Last Answer : To improve voltage at receiving end and power factor

Are we losing control over our life to machines?

Description : Are we losing control over our life to machines?

Last Answer : That is up to you. You can or you can decide to not.

Heat Transfer Machines

Description : Heat Transfer Machines

Last Answer : Heat transfer machines are just the thing you need in order to do heat transfers on your clothing or whatever surface you want to decorate. In order for you to stick designs and precious stones on porous and ... is best. This will also give you an idea of what kind of designs you can choose from.