69 In case there are burrs on the edges of the laminations of the transformer, it is likely to result in
A. Vibrations
B. Noise
C. Higher eddy currents loss
D. Higher hysteresis loss

1 Answer

Answer :

C. Higher eddy currents loss

Related questions

Description : 70] Silicon steel used in laminations mainly reduces A. Hysteresis loss B. Eddy current losses C. Copper loss D. All of the above

Last Answer : A. Hysteresis loss

Description : 19 Transformer cores are built up from laminations rather than from solid metal so that A. Oil penetrates the core more easily B. Eddy current loss is reduced C. Less lamination is required for the windings D. Turn ratio is higher than voltage ratio

Last Answer : B. Eddy current loss is reduced

Description : 43 The purpose of providing an iron core in a transformer is to A.Provide support to windings B. Reduce hysteresis loss C. decrease the reluctance of the magnetic path D. reduce eddy current losses

Last Answer : C. Decrease the reluctance of the magnetic path

Description : 9 Which loss is not common between a transformer and rotating machines? A. Eddy current loss B. Copper loss C. Windage loss D. Hysteresis loss

Last Answer : A. Eddy current loss

Description : 24 Transformer cores are laminated in order to A. simplify its construction B. minimise eddy current loss C. reduce cost D. reduce hysteresis loss

Last Answer : B. Minimise eddy current loss

Description : 17. Which type of loss is not common to transformer and rotating machines? A. Eddy current loss B. Copper loss C. Hysteresis loss D. Windage loss

Last Answer : D. Windage loss

Description : A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and frequency are doubled, the new core losses are (A) 140 W (B) 180 W (C) 240 W (D) 480 W

Last Answer : A transformer at 25 Hz develops 20 W hysteresis loss and 50 W eddy current loss. If the applied voltage and frequency are doubled, the new core losses are 240 W

Description : 60)The noise resulting from vibrations of laminations set by magnetic force, is termed as A. magnetostriction B. boo C. hum D. zoom

Last Answer : C. Hum

Description : 42 The efficiency of a transformer will be maximum when A. copper losses = hysteresis losses B. Hysteresis losses = eddy current losses C. Eddy current losses = copper losses D. Copper losses = iron losses

Last Answer : D. Copper losses = iron losses

Description : 7 The main advantage of auto transformer over a two winding transformer is A. Hysteresis losses are reduced B. Saving in winding material C. Copper losses are negligible D. Eddy losses are totally eliminated

Last Answer : A) hysteresis losses is reduced

Description : 61 The degree of mechanical vibrations produced by the laminations of a transformers depends on A. Tightness of clamping B. Gauge of laminations C. Size of laminations D. All of the above

Last Answer : D. All of the above

Description : The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Last Answer : Answer: C

Description : The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Last Answer : Answer: C

Description : What is hysteresis loss in transformer?

Last Answer : The magneto motive force or mmf applied in the transformer core is alternating. For every cycle due to this domain reversal, there will be extra work done. For this reason, there will be a consumption of electrical energy which is known as Hysteresis loss of transformer.

Description : What is Eddy current loss in transformer?

Last Answer : In transformer, we supply alternating current in the primary, this alternating current produces alternating magnetizing flux in the core and as this flux links with secondary winding, there will be induced ... dissipated as heat. This type of energy loss is called eddy current loss of transformer.

Description : Which of the following properties is not necessarily desirable in the material for transformer core? A. Mechanical strength B. Low hysteresis loss C. High thermal conductivity D. High permeability

Last Answer : C) high thermal conductivity

Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Last Answer : Answer: D

Description : 77 The transformer laminations are insulated from each other by A. Mica strip B. Thin coat of varnish C. Paper D. Any of the above

Last Answer : B. Thin coat of varnish

Last Answer : The thickness of laminations used in a transformer is usually 0.4 mm to 0.5 mm.

Last Answer : The transformer laminations are insulated from each other by thin coat of varnish.

Description : A 220/440 V, 50 Hz, 5 KVA, single phase transformer operates on 220V, 40Hz supply with secondary winding open circuited. Then (A) Both eddy current and hysteresis losses decreases. (B) Both ... same but hysteresis loss increases. (D) Eddy current loss increases but hysteresis loss remains the same.

Last Answer : (A) Both eddy current and hysteresis losses decreases.

Description : 8 The transformer core is laminated to A. Reduce the copper losses B. Reduce the core losses C. Reduce the eddy current losses D. None of the above

Last Answer : C. Reduce the eddy current losses

Description : 10] The main reason for generation of harmonics in a transformer could be A. Fluctuating load B. Poor insulation C. Mechanical vibrations D. Saturation of core

Last Answer : D) saturation of core

Description : The degree of mechanical vibrations produced by the laminations of a transformer depends on?

Last Answer : The degree of mechanical vibrations produced by the laminations of a transformer depends on tightness of clamping, gauge of laminations, size of laminations.

Description : How can eddy current loss be minimized?

Last Answer : By laminating the core.

Description : Mention the factors on which hysteresis loss depends?

Last Answer : (i) Quality and amount of iron in the core (ii) Flux density and (iii) Frequency.

Description : How do we minimize eddy current loss?

Last Answer : A. By laminating the core we can minimize eddy current loss.

Description : How to minimize Hysteresis loss?

Last Answer : By using good magnetic material. By using less value of Magnetic flux density

Description : How to minimize Eddy current loss?

Last Answer : By using less thickness of laminations By using less value of Magnetic flux density

Last Answer : Silicon steel used in laminations mainly reduces hysteresis loss.

Description : The hysteresis and eddy current losses of a single phase transformer working on 200 V, 50 Hz supply are Ph and Pe respectively. The percentage decrease in these when operated on a 160 V, 40 Hz supply are   (a) 32, 36 (b) 20, 36 (c) 25, 50 (d) 40, 80 

Last Answer : The hysteresis and eddy current losses of a single phase transformer working on 200 V, 50 Hz supply are Ph and Pe respectively. The percentage decrease in these when operated on a 160 V, 40 Hz supply are 20, 36

Description : What is the cause of noise in transformer?

Last Answer : The cause of noise in the transformer is mainly because of magnetostriction effect and also loosening of stampings and mechanical forces produced during working.

Last Answer : Noise level test in a transformer is a type test.

Description : The noise produced by a transformer is termed as?

Last Answer : The noise produced by a transformer is termed as hum.

Last Answer : Transformer noise is generated due to vibration of core and winding this is because of magnetostriction and magnetomotive force.

Description : Which of the following losses is/are present in every direct current generator armature? A. Winding copper loss B. Core eddy current loss C. Magnetic hysteresis loss D. All of the above.

Last Answer : Answer: D

Description : As an armature revolves within a magnetic field, friction is developed between the rotated magnetized particles as they pass through each magnetization cycle. This results in ____________. A. copper loss B. eddy-current loss C. hysteresis loss D. armature reaction

Last Answer : Answer: C

Description : A ferrite core has less eddy current loss than an iron core because ferrites have (A) High resistance. (B) Low resistance. (C) Low permeability. (D) High hysteresis.

Last Answer : (A) High resistance.

Description : The armature of a dc machine is laminated to reduce: (A) Eddy current loss (B) Hysteresis loss (C) copper losses (D) friction and windage losses

Last Answer : Ans: A Thinner the laminations, greater is the resistance offered to the induced e.m.f., smaller the current and hence lesser the I2R loss in the core.

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

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

Last Answer : 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 ... loss in transformer is given by, We=Kef2Kf2Bm2watts Skin effect limitations:

Description : Transformer cores are laminated to reduce _____________. A. eddy currents B. secondary flux C. leakage flux D. all of the above

Last Answer : Answer: A

Description : 71 High frequency transformers sometimes make use of ferrite cores because it has A. High specific gravity B. High resistance C. High hysteresis D. low permeability

Last Answer : B. High resistance

Description : 72 Harmonics in transformer result in A. Increased core losses B. Increased I2R losses C. Magnetic interference with communication circuits D. All of the above

Last Answer : D. All of the above

Last Answer : The short circuit in any winding of the transformer is the result of impulse voltage.

Description : A control system with excessive noise, is likely to suffer from (a) saturation in amplifying stages (b) loss of gain (c) vibrations (d) oscillations

Last Answer : Ans: A

Last Answer : The use of higher flux density in the transformer design reduces weight per kVA.

Description : [53] The iron loss of the transformer is negligible during short circuit test because A. The entire input is just sufficient to meet Cu losses only B. Flux produced is a small fraction of the normal flux C. Iron core becomes fully saturated D. Supply frequency is held constant

Last Answer : B. Flux produced is a small fraction of the normal flux

Description : 49 The open circuit test is carried out in a transformer to find the A. Cu loss B. Core loss C. Total loss D. Insulation resistance

Last Answer : B. Core loss