Use of dc motor

by

1 Answer

Answer :

There are three types of self excited DC motor

1. series wound

2. shunt wound

3, compound wound

1.Applications of DC series motor are :

  • DC series motor is use for high speed applications.
  • DC series motor is use for electrical traction.
  • DC series motor is use for Crane.
  • DC series motor is use in vacuum cleaner.
  • DC series motor is use in trains.

These are some applications of DC series motor,


2.Applications of DC shunt motor are : 

  • DC shunt motor are use for lathe machine.
  • DC shunt motor is use for compressor.
  • DC shunt motor is use for drilling.
  • DC shunt motor is use for grinders.

These are some applications of DC shunt motor.


3.Applications of DC compound motor are :

  • DC compound motor is use for elevators.
  • DC compound motor is use for rolling mill.
  • DC compound motor is use for punches.

These are some applications of DC compound motor.

by

Related questions

Application of DC Series Motor

Description : Application of DC Series Motor

Last Answer : 1. Electric traction 2. Cranes, 3. Passenger elevators, 4. Continuous conveyors, 5. Grinders, 6. Polishers,

separately excited dc motor controlled by chopper with a frequency of 500hz and source voltage of 230v and rated value of motor is ...

Description : separately excited dc motor controlled by chopper with a frequency of 500hz and source voltage of 230v and rated value of motor is 220v 24A 100 rpm find its duty ratio at 1.2 times rated torgue and 500rpm

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

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

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

Last Answer : With three phase induction motor, humming and not rotate, but if single phase universal motor like air blower, home mixture, motor run on constant speed..speed variation not possible...

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

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

Last Answer : Function : i) Yoke: The yoke serves the following two purposes. i) It supports the other components such as poles and provides mechanical protection for whole machine. ii) It forms a part of ... one pole to another and thus to help the motor to develop a continuous and unidirectional torque  

DC series motor should never be started at no-load. Justify.

Description : DC series motor should never be started at no-load. Justify. 

Last Answer : At no load the field current (which is also the armature current) is very small and hence the useful air-gap field flux. Also the torque is very small.  As N ∝ 1/Ф the speed rises to ... on the rotating parts they may get damaged. Hence DC series motor should never be started on no-load.

With the help of neat diagrams,explain the following methods of speed control in DC series motor. i) Field diverter method. ii) Armature diverter method.

Description : With the help of neat diagrams,explain the following methods of speed control in DC series motor. i) Field diverter method. ii) Armature diverter method.

Last Answer : (i) Field diverter method: - Resistance connected in parallel with field winding -By adjusting this resistance current can by diverted from field winding -Thus field current decreases and the speed can be ... decreased, the flux must increase and hence speed is decreased than the rated speed.

What is back emf in DC motor? Explain its significance.

Last Answer : Back emf: When the armature of DC motor rotates under the fixed magnetic field and cuts it, by Faraday's law an emf is induced in them. The induced emf acts in opposite direction to the ... the flow of armature current i.e. it automatically changes the armature current to meet load requirements. 

State the principle of operation of a dc motor.

Last Answer : Principle of operation of a dc motor: When a current carrying conductor is placed in a magnetic field, the conductor experiences the mechanical force. The magnitude of force is given by  F = BIL newton  where F – Force , B – Maximum flux density , I – Current , L – Active length of conductor

Give the two functions of yoke in DC motor.

Description : Give the two functions of yoke in DC motor. 

Last Answer : Functions of yoke in DC motor: 1) Provides mechanical support for poles. 2) Acts as protecting cover for machine. 3) Provides path for magnetic flux.

State any two applications of brushless DC motor.

Description : State any two applications of brushless DC motor. 

Last Answer : 1) Synthetic fibre drawing works.  2) Turn table drives in record players.  3) Spindle drives in hard disk circuits.  4) Computer peripheral equipments as plotters etc. 5) Gyroscope motors.  6) Biomedical machines as heart pumps. 

With the help of necessary sketch, explain in brief the working of brushless DC motor.

Description : With the help of necessary sketch, explain in brief the working of brushless DC motor. 

Last Answer : Constructional Diagram of Brushless DC Motor: Working of brushless DC motor: The brushless DC motor is the combination of a permanent excited synchronous motor and a frequency ... Suitable PWM techniques allow regenerative breaking, which increases dynamic and efficiency of the drive. 

List the various losses on a DC Motor.

Description : List the various losses on a DC Motor. 

Last Answer : The various losses on a DC Motor: 1) Winding losses (Copper losses): i) Armature winding losses ii) Shunt field losses iii) Series field losses 2) Core losses (iron losses): 3) Brush contact losses: 4) Windage and frictional (Mechanical losses):

A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling

Description : A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling diode is open circuited, then the motor :  (A) can be operated in first quadrant (B) ... in first & second quadrants (C) can be operated in first & fourth quadrants (D) cannot be operated

Last Answer : A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling diode is open circuited, then the motor : can be operated in first & fourth quadrants

In a DC motor, it is important to place the brushes along ______

Description : In a DC motor, it is important to place the brushes along ______ A) Magnetic Neutral Axis B) Normal Geometric Axis C) Nominal Geometric Axis D) None of these

Last Answer : In a DC motor, it is important to place the brushes along Magnetic Neutral Axis

In a 4-pole wave winding connected dc motor, the cross-magnetizing AT/pole for a brush shift of θ radians

Description : In a 4-pole wave winding connected dc motor, the cross-magnetizing AT/pole for a brush shift of θ radians (A) Armature amp-conductors × (θ/360o) (B) Armature amp-turns × (θ/360o) (C) Armature amp-conductors × (1/4 - θ/360o) (D) Armature amp-conductors × (1/8 - θ/360o)

Last Answer : In a 4-pole wave winding connected dc motor, the cross-magnetizing AT/pole for a brush shift of θ radians Armature amp-conductors × (1/8 - θ/360o)

In a differentially compounded dc motor

Description : In a differentially compounded dc motor (A) the speed is constant as the torque increases (B) the speed falls non-linearly as the torque increases (C) the speed increases non-linearly as the torque increases (D) the flux increases as the load increases

Last Answer : In a differentially compounded dc motor the speed increases non-linearly as the torque increases

A large dc motor is required to control the speed of the blower from a 3 -phase ac source. The suitable ac to ...

Description : A large dc motor is required to control the speed of the blower from a 3 -phase ac source. The suitable ac to dc converter is, 3 -phase (a) Fully controlled bridge converter ( ... bridge converter with freewheeling diode (c) Half controlled bridge converter (d) Converter pair in sequence control

Last Answer : a fullu control

A DC shunt motor having unsaturated magnetic circuit runs at 1000 rpm with rated voltage If the applied ...

Description :  A DC shunt motor having unsaturated magnetic circuit runs at 1000 rpm with rated voltage If the applied voltage is reduced to half of the rated voltage, the motor will run at (A) 2000 rpm (B) 1000 rpm (C) 750 rpm (D) 500 rpm

To enable dc series motor work satisfactory with an AC supply, the following modifications should be done...

Description : To enable dc series motor work satisfactory with an AC supply, the following modifications should be done (1) The yoke and poles should be completely laminated (2) The poles should be made of ... (3) The air gap between stator and rotor be reduced (4) Compensating poles should be introduced  

A dc series motor when connected across an AC supply will

Description : A dc series motor when connected across an AC supply will (1) Develop torque in same direction (2) Not develop any torque (3) Draw dangerously high current (4) Develop a pulsating torque 

A dc shunt motor runs at 500 r.p.m at 220 V. A resistance of 4.5 Ω is added in series with the armature for...

Description : A dc shunt motor runs at 500 r.p.m at 220 V. A resistance of 4.5 Ω is added in series with the armature for speed control. The armature resistance is 0.5 ohms. The current to stall the motor will be (1) 44 A (2) 50 A (3) 44.4 A (4) 60 A  

The dc motor used for intermittent high torque loads is

Description : The dc motor used for intermittent high torque loads is  (1) dc series motor (2) dc shunt motor (3) differential compound motor (4) cumulative compound motor

Last Answer : 4 cumulative compound motor

A cumulative dc compound motor runs at 1500 rpm. on full load. If its series field is short-circuited, its speed

Description : A cumulative dc compound motor runs at 1500 rpm. on full load. If its series field is short-circuited, its speed  (1) becomes zero (2) remains unchanged (3) increases (4) decreases

Last Answer : Increases. As it's cumulative compound motor, both series and shunt field both assist each other. If series field is short circuited, the overall field strength will decrease and atop of that ... speed is inversely proportional to field strength.  So, the speed will increase overall.

If the back emf of a dc motor is doubled and its speed is also doubled, the torque developed in the machine...

Description : If the back emf of a dc motor is doubled and its speed is also doubled, the torque developed in the machine will  (1) get doubled (2) become 4 times (3) get halved (4) remain unaltered

The method of speed control used for increasing the speed of a dc shunt motor above its rated speed is

Description : The method of speed control used for increasing the speed of a dc shunt motor above its rated speed is  1) armature resistance control 2) field control (3) armature voltage control (4) series parallel control 

A separately excited dc motor is required to be controlled, from a 3-phase supply, for its operation in the first...

Description : A separately excited dc motor is required to be controlled, from a 3-phase supply, for its operation in the first quadrant only. The most preferred converter would be  (a) 3-phase fully controlled ... converter with free wheel diode (c) 3-phase dual converter (d) 3-phase half wave converter 

Last Answer : A

Variation in dc excitation of a synchronous motor causes variation in

Description : Variation in dc excitation of a synchronous motor causes variation in   (a) Speed of motor (b) Power factor (c) Armature current (d) Both armature current and power factor 

Armature shunting method of speed control of dc shunt motor is preferred over annature resistance method...

Description : Armature shunting method of speed control of dc shunt motor is preferred over annature resistance method due to:  (1) Better speed regulation (2) Less loss in external resistance (3) Simplicity in control circuit (4) Reduced cost of controller

Last Answer : Armature shunting method of speed control of dc shunt motor is preferred over annature resistance method due to: Better speed regulation.

A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, having a flux of 0.4 me and total...

Description : A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, having a flux of 0.4 mWb and total number of conductors 1000. The value of e.m.f. will be:  (A) 100 Volts (B) 0.1 Volts (C) 1 Volts (D) 10 Volts

A 750 Hp, 250 V, 1200 r/min DC motor is connected to a 208 V, 3 phase, 60 Hz, line using a 3 phase bridge...

Description : A 750 Hp, 250 V, 1200 r/min DC motor is connected to a 208 V, 3 phase, 60 Hz, line using a 3 phase bridge converter. The full load armature current is 2500 A and the armature resistance is 4 m ohm. Calculate ... angle under rated full load conditions.  (A) 45 deg (B) 208 deg (C) 27 deg (D) 32 deg 

If the load current and flux of a DC motor are held constant, and voltage applied across its armature is...

Description : If the load current and flux of a DC motor are held constant, and voltage applied across its armature is increased by 10%, its speed will:  (A) Decrease by 10%. (B) Remain unchanged. (C) Increase by 10%. (D) Increase by 20%. 

What is the order of the characteristic equation of an armature controlled DC motor?

Description : What is the order of the characteristic equation of an armature controlled DC motor?  (A) First order equation (B) Second order equation (C) Zero order equation (D) Third order equation 

Last Answer : third order

Which type of starter is used to start the DC motor?

Description : Which type of starter is used to start the DC motor?

What are the advantages of DC series motor?

Description : What are the advantages of DC series motor?

Why dc series motor should not be started at no load?

Description : Why dc series motor should not be started at no load?

Why a dc series motor has a high starting torque?

Description : Why a dc series motor has a high starting torque?

Last Answer : motor

What is the principle of DC motor?

Description : What is the principle of DC motor?

Last Answer : principle

What is the back EMF of a dc motor?

Description : What is the back EMF of a dc motor?