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

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

1 Answer

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 the magnetic circuit & provides the path of low reluctance for the magnetic flux. 


ii) Pole: The pole shoe serves two purposes i) They spread out flux in the air gap & their large cross section reduces the reluctance of the magnetic path ii) They support the exciting coils or field coils. 


iii) Field winding: For excitation of poles 


iv) Commutator: The function of the commutator is to reverse the current in each conductor of the armature as it passes from one pole to another and thus to help the motor to develop a continuous and unidirectional torque  

by

Related questions

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.

Last Answer : Part Function Material Yoke -Provides mechanical support for poles -Acts as protecting cover for machine -Provides path for magnetic flux Cast Iron OR Cast Steel Field Winding - ... Pole core  Provides mechanical support to field winding. Cast Iron OR Cast Steel

List the main parts of D.C. motor

Description : List the main parts of D.C. motor

Last Answer : Main parts of D.C. motor and their functions:  Part Functions Yoke i) Provides mechanical support for poles. ii) Acts as protecting cover for machine. iii) Carries magnetic flux. ... a fixed physical position relative to the stator.  Shaft Used to transfer mechanical power 

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

Description : The function of a brush and commutator arrangement in a dc motor is to  (1) produce unidirectional torque (2) produce unidirectional current in the armature (3) help in changing the direction of rotation of the armature (4) reduce sparking

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

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)

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 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

Sparking at the commutator of a D.C. motor may result in?

Last Answer : Sparking at the commutator of a D.C. motor may result in damage to commutator segments, damage to commutator insulation, increased power consumption.

Field control of DC motor

Description : Field control of DC motor

Last Answer : Field control of DC motor

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...

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

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

State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.

Description : State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.

Last Answer : Modifications are necessary in a dc series motor so that it operates satisfactorily on ac supply. The modifications are as follows:  1) AC series motor is built with a few field turns as ... and grinders 5) High speed vacuum cleaners 6) Sewing machines 7) Food processors 8) Drilling machine 

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

DC MOTOR MCQ

Description : DC MOTOR MCQ

Last Answer : 101. Which of the following loss in a D.C. generator is dissipated in the form of heat? (a) Mechanical loss (b) Core loss (c) Copper loss (d) All of the above Ans: d 102. Which of the following ... (b) does not run as a generator (c) also runs as a motor comes to stop after sometime Ans: a

DC motor gross torque example

Description : DC motor gross torque example

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%; }

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%; }

DC motor brake test numerical

Description : DC motor brake test numerical

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%; }

Brake test on DC series motor

Description : Brake test on DC series 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%; }

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.

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

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

Last Answer : Electric trains require an inverse torque speed characteristics for proper operation. That is a higher torque is required at start (when speed is nil or low) and as the train picks up ... torque - speed characteristics of DC series motors match, these motors are suitable for electric trains

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

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

Description : 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 half full load in N -m is :

Last Answer : 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 half full load in N -m is : 0.075

The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a

Description : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ (A) directly proportional to α and Φ (B) ... proportional to α and inversely proportional to Φ (D) directly proportional to Φ and inversely proportional to α

Last Answer : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ directly proportional to α and inversely proportional to Φ

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.

What are the speed control methods of dc motor?

Description : What are the speed control methods of dc motor?

Last Answer : Field control of DC motor Armature control of DC motor

is induction motor ac or dc?

Last Answer : Induction motor is a AC motor it is also known as asynchronous motor .

Chopper controlled DC motor

Description : Chopper controlled DC motor

Last Answer : Chopper controlled DC motor

Armature control of DC motor

Description : Armature control of DC motor

Last Answer : Armature control of DC motor

Separately Excited DC motor

Description : Separately Excited DC motor

Last Answer : Separately Excited DC motor

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.

In a differentially compounded D.C. motor, if shunt field suddenly opens?

Last Answer : In a differentially compounded D.C. motor, if shunt field suddenly opens the motor will first stop and then run in opposite direction as series motor.

If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens?

Last Answer : If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses.

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.

What are the main parts of a generator?

Description : What are the main parts of a generator?

Last Answer : the main parts of the generator are as follows yoke Armature Poles field winding Prime mover  Commutator Shaft Bearings Brushes

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. 

Last Answer : Necessity of Starter for D.C. Motor: Armature current is given by equation Ia = (V−Eb)/Ra i) If the motor is at standstill or rest, back emf Eb is zero (as Eb= ZNP/(60A), at start speed N ... . Types of D.C. motor starters: i) Two point starter ii)Three point starter iii) Four point starter

Define: i) Q point ii) DC loadline iii) Need of biasing iv) Current gain

Description : Define: i) Q point ii) DC loadline iii) Need of biasing iv) Current gain

Last Answer : i) Q point: It is the point on the load line which represents the dc current through a transistor (ICQ) and the voltage across it (VCEQ), when no ac signal is applied.  ii) DC load line: The ... region is as desired.  iv) Current Gain: It is a ratio of output current to input current.

State the function of commutator in DC generator and name the material used for commutator.

Description : State the function of commutator in DC generator and name the material used for commutator.

Last Answer : Function of Commutator: Commutator converts AC induced in armature winding into DC for external load. Material: i) Commutator segments are made up of Copper. ii) Commutator segments are insulated from each other by Mica.

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

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

Last Answer : Series motor has got maximum self relieving property.

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

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