search
person
Explain hysteresis loss, eddy current loss and skin effect limitations with reference to magnetic material.

1 Answer

 
done_all

Hysteresis loss:

Hysteresis loss is a loss which occurs due to the friction of magnetic domain due to the change in magnetic field in ferromagnetic material like iron. Hysteresis loss causes power loss and heat and insulation damage. The figure shows the hysteresis loop. if the loop is fat then hysteresis losses will be more and if the hysteresis loop is thin then hysteresis losses will be less. If the coercive force is high hysteresis loop will be fat and if the coercive force is low hysteresis loop will be thin. Hysteresis loss reduces the efficiency. Hysteresis loss cannot be completely removed but it can be reduced by choosing the material with less hysteresis loop area. Because less hysteresis loop area material will have low hysteresis loss.


Hysteresis loss in transformer is given by,

W= Kf (Bm)1.6 watts


image


Eddy current loss:

Eddy current also increases heat in the circuit. The loss due to eddy current is known as eddy current loss. Eddy current is caused due to the alternating current which induced emf and that induced emf produce current this current is called eddy current. 

Suppose a coil is wound on a core. An alternating current is applied to the coil. This alternating current to the coil will produce alternating flux. Now according to Faraday's law of electromagnetic induction, this changing flux will generate induced emf in the core. This induced emf will cause current to flow in the core. This flow of current is called eddy current and the losses due to eddy current are called eddy current loss. Eddy current causes I2R losses means heat. If there is a solid core with less resistance then eddy current will be high. Eddy current reduces the efficiency. Complete removal of eddy current is not possible but it can be reduced.

image

Eddy current can be reduced by using laminated core and by using the material with the high resistivity magnetic material. High resistivity magnetic material like silicon.


Eddy current loss in transformer is given by,

We=Kef2Kf2Bm2watts


Skin effect limitations:


thumb_up_alt 0 like thumb_down_alt 0 dislike

Related questions

Description : What is the difference between eddy current and hysteresis loss?

Answer : Loss occurred by magnetising and demagnetising process is called histerisis loss and the current flowed due to the magnetic field produced by the electric field applied is called eddy current losses

Description : In a magnetic material hysteresis loss takes place primarily due to?

Answer : In a magnetic material hysteresis loss takes place primarily due to it high retentivity.

Description : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is :  (A) 256 W (B) 320 W (C) 500 W (D) 625 W

Answer : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : 625 W

Description : A ferrite core has less eddy current loss than an iron core because?

Answer : A ferrite core has less eddy current loss than an iron core because ferrites have high hysteresis.

Description : The skin effect in conductors is due to non uniform distribution of current in it and major portion of current is near the _______ of conductor.  (1) Surface (2) Center (3) Complete cross section area (4) Axis

Answer : The skin effect in conductors is due to non uniform distribution of current in it and major portion of current is near the Surface of conductor. 

Description : If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be?

Answer : If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be large.

Description : Skin effect occurs when a conductor carries current at_____ frequencies.

Answer : Skin effect occurs when a conductor carries current at high frequencies.

Description : explain skin effect in copper interconnects. what are the various ways of reducing this effect?

Answer : Skin effect generally observed in ac conductor in transmission network, in skin the current flowing through outer layer of conductor is more than iner area of conductor thus we can say the ... for reducing this effect we can use boundel conductor or used hollow conductor for power transmission

Description : State the factors affecting hysteresis loss.

Answer : i) Flux density ii) Frequency iii) Volume of the magnetic material iv) Nature of magnetic material

Description : State the meaning of skin effect and how can it be minimised. 

Answer : Meaning of skin effect :  When alternating current flows through conductor it has tendency to flow away from center of conductor. i.e. maximum current density is near skin of conductor and goes on ... whenever possible as Skin effect is absent (Since frequency 0) instead of A.C. supply.  

Description :  State the disadvantages of skin effect.

Answer : Disadvantages of skin effect:- 1. Full cross section of conductor is not utilized, Therefore effective area of conductor reduces so its resistance increases. 2. Due to increase in resistance, copper ... increases (Since Voltage drop = IR ) 5. So voltage regulation becomes poor (increases) 

Description : Skin effect is absent in which of the following transmission systems? A) Extra High Voltage (EHV) AC B) High Voltage Direct Current (HVDC) C) Both A and B D) None of these

Answer : Skin effect is absent in which of the following transmission systems? A) Extra High Voltage (EHV) AC B) High Voltage Direct Current (HVDC) C) Both A and B D) None of these

Description : when the skin effect occurs ?

Answer : skin effect is occur at higher frequencies when skin depth is smaller

Description : what is skin effect?

Answer : Skin effect is occurs in conductor due to high frequency...as the frequency increases the resistance of conductor increases...skin effect means the current flow through the skin of conductor....as the ... dc current their will be no skin effect...I hope you understand basic concept of skin effect

Answer : As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for sound equipment.

Description : What is magnetic hysteresis? What is the cause of hysteresis?

Answer : Magnetic hysteresis: When a magnetic material is subjected to cycle of magnetization, it is found that flux density (B) in the material lags behind applied magnetizing force (H). This ... the movement of orientation, due to which the flux density lags behind the magnetic field intensity.

Description : Explain magnetic effect employed in measuring instrument.

Answer : Magnetic Effect:  I) In PMMC meters:  ➢ When a current is passed through a conductor, magnetic field is produced round the conductor. Due to this field when current ... field it experiences a mechanical force.  Examples: Electrodynamometer type instruments, Induction type instrument. 

Description : Give two applications of each : 1) Eddy current sensor 2) Optical sensor.

Answer : Eddy current sensor : 1. Detection of non-magnetic but conductive materials. 2. Displacement sensing 3. Position sensing Optical sensor : 1. Position Detection 2. Velocity Detection 3. Acceleration Detection 4. Direction Detection

Description : Which of the following can reduce the Eddy current losses? A) By making the core of a stack of plates electrically insulated from each other B) By making the core of solid block C) By increasing the applied voltage  D) None of these

Answer : Which of the following can reduce the Eddy current losses? A) By making the core of a stack of plates electrically insulated from each other B) By making the core of solid block C) By increasing the applied voltage  D) None of these

Description : Eddy current damping cannot be used for moving iron instrument because

Answer : Eddy current damping cannot be used for moving iron instrument because the presence of a permanent magnet required for such purpose would affect the deflection and hence the reading of the instrument

Answer : The disc of an instrument using eddy current damping should be of conducting and non-magnetic material.

Description : How eddy current can be minimized?

Description : How eddy current is produced in a transformer?

Description : what is eddy current ?

Answer : In magnetic circuits when we supply current to coil which wound on some core( of iron cast iron, ferrite ) material it produce magnetic field but there is small amount of flux which also ... heat and losses in magnetic circuits..for good working conditions we always try to minimize eddy current

Description : What is piezoelectric effect? Name two piezoelectric material.

Answer : piezoelectric effect: Piezoelectric effect can be stated as follows: when a pressure or force or vibration is applied to crystalline material like quartz crystal or crystalline substances, then ... crystal: Quartz crystal ,Rochelle salt 2) Synthetic crystals : Barium Titanate, Lithium sulphate

Answer : Yes, Induction heating is used for both magnetic and non-magnetic materials.

Description : State the material used for making (1) Magnetic Core (2) Fuse element  

Answer : The material used for making of:  (1) Magnetic Core : Iron, cobalt, Nickel, CRGO, HRGO , silicon steel  (2) Fuse Element: Tin- lead wire, Tinned copper wire 

Description : The magnetic susceptibility of paramagnetic material is: A) Less than zero B) Less than one but positive C) Greater than one D) Equal to zero

Answer : The magnetic susceptibility of paramagnetic material is: Less than one but positive

Description : The property of a material which opposes the creation of magnetic flux in it is known as?

Answer : The property of a material which opposes the creation of magnetic flux in it is known as reluctance.

Description : A material for good magnetic memory should have?

Answer : A material for good magnetic memory should have high retentivity.

Description : Explain the hysteresis loop of a magnetic material with neat diagram.

Answer : Hysteresis loop of magnetic material:  The circuit arrangement for plotting the hysteresis loop is shown in figure given below. The electromagnetic part consists of a coil wound on the iron ring ... one magnetic reversal is called hysteresis loop. Meaning of hysteresis is to lag behind.

Description : Define armature reaction in an alternator. Explain the effect of armature reaction at various P.F. of loads of alternator.

Answer : Armature Reaction: The effect of armature flux on main flux is called as armature reaction.  Armature Reaction at Various Power Factors: When armature is loaded, the armature flux modifies ... lagging p.f. For capacitive loads the effect of flux is partly distorting and partly strengthening.

Description : Classify magnetic materials and explain in brief.

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 { ... the absence of external magnetic field. Following are the ferromagnetic materials: Iron, Cobalt, Nickel.

Description : In a loss-free R-L-C circuit the transient current is?

Answer : In a loss-free R-L-C circuit the transient current is sinusoidal.

Description : With the help of N-channel JFET describe the effect of input voltage VGS on output current ID.

Answer : Working of N channel FET: * When a voltage is applied between the drain and source with a DC supply (VDD), the electrons flows from source to drain through narrow channel ... where the channel gets completely blocked and the drain current becomes zero is called pinch- off voltage. 

Description : Analyze the effect of supply voltage on performance of LED as regards current, Lumen output, efficacy and life. 

Answer : 1) Effect on Current:- In LED current depends upon supply voltage, if voltage get changes then current also change but this change in current will be control by resistors which are connected in series.  2) ...   4) Effect on Life:- If supply voltage is not stable then life of LED get reduced. 

Answer : The chemical effect of current is used in D.C. ammeter hour meter.

Description : How can a magnetic field be used to generate an electric current?

Answer : Magnetic  field  can  be  used  to  generate  electric  current  on  a  condition  that  it  is  on  a  rate  of  changing  magnetic  flux.  (Faraday's  law)

Description : Explain the characteristics of inductor to be considered while designing it. What is the effect of over current and increase in temperature on inductor.

Description : Explain why potential difference is necessary to produce current in a circuit.

Description : List and state any four limitations of inter connected power station.

Answer : Limitations of inter connected power station:- 1) Initial cost of infrastructure of transmission line increases as length increases. 2) Interconnection required more automation which increases cost on ... capacity. But in absence of surplus power merits of interconnection cannot be obtain.

Description : State any two limitations of wind energy.

Answer : Limitations of wind energy: 1) Wind turbine produces noise. 2) Its efficiency is less (20% to 30%) 3) There is limitation on site selection. 4) Transportation cost of wind tower and accessories is high ... No firm power. 7) Power generation is not in phase with the demand. 8) Generation is costly.

Description : For heating a magnetic material using induction heating, the hysteresis and eddy current losses are respectively proportional to (a) f and f 2 (b) f 2 and f (c) f and f (d) none of the above 

Description : (i) Explain the process of diffusion in semiconductor material. (ii) Explain Hall effect.

Answer : (i) Diffusion: In a semi conductor bar a concentration gradient exist when either number of electrons or holes is greater in one region of a semi conductor as compared to other region. When ... to determine whether a semiconductor is N type or P type, and to find carrier concentration

Description : Explain the electrical losses of magnetic materials used for the cores of inductors and transformer.

Description : Describe with neat sketch working of hysteresis motor.

Answer : Working: When stator is energized with single phase ac supply, rotating magnetic field is produced because of starting (auxiliary) and main windings, which remain in circuit permanently. The ... the principle of magnetic locking this motor either rotates at synchronous speed or not at all.

Description : The term hysteresis is associated with (A) On-Off control (B) P-I control (C) Feed forward control (D) Ratio control

Answer : The term hysteresis is associated with On-Off control

Description : Eddy currents are induced in the pole shoes of a D.C. machine due to?

Answer : Eddy currents are induced in the pole shoes of a D.C. machine due to relative rotation between field and armature.

Description : How eddy currents are generated?

Description : How to care for your skin during the cold season?

Answer : How to care for your skin during the cold season? The skin of our hands and face is influenced by climatic conditions. The cold on the face and hands constricts blood vessels, so blood circulation is ... is necessary to drink a sufficient amount of liquid - at least 1.5 liters of water per day.

← Prev Question Next Question →
editAsk a Question
...