If the frequency of input voltage of a transformer is increased keeping the magnitude of voltage unchanged, then: A) both hysteresis loss and eddy current loss in the core will increase B) hysteresis loss will increase but eddy current loss will decrease C) hysteresis loss will decrease but eddy current loss will increase D) hysteresis loss will decrease but eddy current loss will remain unchanged

1 Answer

Answer :

 If the frequency of input voltage of a transformer is increased keeping the magnitude of voltage unchanged, then: hysteresis loss will decrease but eddy current loss will remain unchanged

Related questions

Description : The rating of the Transformer __ when the supply frequency is increased: a) Remains unchanged b) Increases c) Decreases d) None of the above

Last Answer : Ans: B

Last Answer : If the supply frequency to the transformer is increased, the iron loss will increase.

Last Answer : When a given transformer is run at its rated voltage but reduced frequency, its core flux density is increased.

Description : Production rate __________ with increased fineness, with a given energy input to the size reduction machine. (A) Decreases (B) Increases (C) Remains unchanged (D) May increase or decrease; depends on the machine

Last Answer : (A) Decreases

Description : In a power transformer, the fundamental frequency of the hum arising due to magnetostriction is  (a) equal to the line frequency (b) double the line frequency (c) 4 times the line frequency (d) not related to the line frequency

Last Answer : In a power transformer, the fundamental frequency of the hum arising due to magnetostriction is double the line frequency

Last Answer : The core used in high frequency transformer is usually air core .

Description : State and justify which of the following two transformers is better:  Transformer A = 4% voltage regulation  Transformer B = 6% voltage regulation

Last Answer : Transformer A with 4% voltage regulation is better.  Justification: Voltage regulation refers to the percentage change in secondary voltage when load is changed from no-load to full-load with primary voltage ... 4% voltage regulation, which is less as compared to 6% of transformer B, it is better.

Description : The voltage applied to the H.V. side of a transformer during S.C. test is 2% of the rated voltage. The core loss as the fraction of its rated core loss is (a) 4% (b) 0.4% (c) 0.25% (d) 0.04%

Last Answer : 0.04%

Description : In a transformer the voltage regulation will be zero when it operates at (A) unity p.f. (B) leading p.f. (C) lagging p.f. D) zero p.f. leading.

Last Answer : In a transformer the voltage regulation will be zero when it operates at leading p.f.

Description : If the secondary turns of a transformer are doubled and at the same time primary voltage is reduced to half then the secondary voltage will

Last Answer : If the secondary turns of a transformer are doubled and at the same time primary voltage is reduced to half then the secondary voltage will not change

Description : In a transformer, low voltage winding is placed near the core in case of concentric windings so as to  1. Reduce the leakage flux 2. Reduce the insulation requirement 3. Reduce the risk of voltage shock in case of insulation breakdown 4. Reduce the ... a) 1, 2, 3 (b) 2, 3, 4 (c) 1, 2, 3, 4 (d) 2, 3

Last Answer : In a transformer, low voltage winding is placed near the core in case of concentric windings so as to  1. Reduce the leakage flux 2. Reduce the insulation requirement 3. Reduce the risk of voltage shock in case of insulation breakdown 4. Reduce ... ) 1, 2, 3 (b) 2, 3, 4 (c) 1, 2, 3, 4 (d) 2, 3

Description : In a transformer, zero voltage regulation at full load is   (a)Not possible   (b) Possible at unity power factor load   (c) Possible at leading power factor load   (d) Possible at lagging power factor load

Last Answer : In a transformer, zero voltage regulation at full load is Possible at leading power factor load 

Last Answer : A transformer cannot raise or lower the voltage of a D.C. supply because Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero.

Last Answer : The no load current in a transformer lags behind the applied voltage by an angle of about 75°.

Description : In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are?

Last Answer : In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are hysteresis and eddy current losses.

Description : A good voltage regulation of a transformer means?

Last Answer : A good voltage regulation of a transformer means output voltage fluctuation from no load to full load is least.

Description : The voltage transformation ratio of a transformer is equal to the ratio of?

Last Answer : The voltage transformation ratio of a transformer is equal to the ratio of secondary induced e.m.f. to primary induced e.m.f.

Description : If a transformer is switched on to a voltage more than the rated voltage?

Last Answer : If a transformer is switched on to a voltage more than the rated voltage its power factor will deteriorate.

Description : If the length of an antenna is changed from 2.5 meters to 2.8 meters, its resonant frequency will A. increase B. depend on the velocity factor so the resonant frequency can either be increased or decreased C. will be unchanged D. decrease

Last Answer : D. decrease

Description : For given applied voltage, with the increase in frequency of the applied voltage?

Last Answer : For given applied voltage, with the increase in frequency of the applied voltage eddy current loss will remain unchanged.

Description : In the impact problems the following conditions must always be satisfied a.The total kinetic energy remains unchanged b.The total linear momentum remains unchanged c.The magnitude of the total linear ... is reduced by a factor proportional to the coefficient of restitution e.None of the above

Last Answer : b. The total linear momentum remains unchanged

Description : The zero flag of 8085 microprocessor is to be set keeping the content of the accumulator unchanged. Which instruction is to be used?  (a) MOV A,A (b) ANI 00H (c) XRA A (d) CMP A

Last Answer : The zero flag of 8085 microprocessor is to be set keeping the content of the accumulator unchanged. Which instruction is to be used?  (a) MOV A,A (b) ANI 00H (c) XRA A (d) CMP A

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 : A load with an impedance of 440 ohms is connected across the secondary of the transformer illustrated. If the input voltage is 110 VAC and the step-up ratio is 10 to 1, what will be the primary current? EL-0055 A. 2.5 amps B. 25 amps C. 250 amps D. current cannot be determined with information given

Last Answer : Answer: B

Description : A load is connected to the secondary of the transformer illustrated and the current through the load is 10 amps. If the step-up ratio is 10 to 1 and the input voltage is 110 VAC, what will be the current flow through the primary? EL-0055 A. 1 amp B. 10 amps C. 100 amps D. 1000 amps

Last Answer : Answer: C

Description : When a low input voltage is imparted to a device which then delivers a high output voltage, the device is known as a _____________. A. primary transformer B. secondary transformer C. stepdown transformer D. stepup transformer

Last Answer : Answer: D

Description : In the illustrated circuit, if the input to leads 'B' and 'Y' was 24 VDC the output between 'A' and 'X' will be _________. EL-0069 A. 24 VDC B. 22.8 VDC, 24 VDC minus the 1.2 VDC voltage drop across two diodes C. undeterminable without knowing the turns ratio of the transformer D. 0 VDC

Last Answer : Answer: D

Description : The voltage at the reference electrode of the circuit shown in the illustration is applied to the input of a/an ______________. EL-0090 A. class A detector whose output drives an ... drives an 2-stage isolation transformer D. magnetic amplifier whose output controls a saturable reactor

Last Answer : Answer: D

Description : If output voltage is greater than input voltage, then transformer is A. step up B. step down C. faulty D. fatal

Last Answer :  step up

Description : In addition to stepping up or stepping down the input line voltage, what additional purpose does the transformer serve?

Last Answer : . It isolates the chassis from the power line.

Description : What is the quantity that remains unchanged in a transformer?

Last Answer : Frequency

Description : Explain direct loading test on single phase transformer with neat circuit diagram. 

Last Answer : Direct loading test on single phase transformer with neat circuit diagram:   Direct loading test on transformer is carried out to calculate the losses, efficiency and voltage regulation of the ... voltage.  Efficiency and regulation can be calculated by using following formulae:   

Description : Explain the effect of Harmonics on the Transformer.

Last Answer : Effect of Harmonics on the Transformer:  1. Core loss: Harmonic voltage increases the hysteresis and eddy current losses in the lamination. The amount of the core loss depends on ... small core vibrations.  5. Saturation problem: Sometimes additional harmonic voltage causes core saturation.

Description : List two special feature of welding transformer.

Last Answer : Special features of welding transformer: i) It is a step down transformer that reduces the source voltage to a voltage desired according to the demands of the welding process. ii) Having large primary turns and less ... V ii) Secondary voltage - 40 to 60 V iii) Secondary current - 200 to 600 A

Description : State two applications of isolation transformer

Last Answer : Applications of isolation transformer: i) Isolates the load equipment from supply ground: ii) Reduction of voltage spikes iii) It acts as a decoupling device. iv) Protects loads from harmonic distortion.

Description : State why a transformer always have an efficiency of more than 90%.

Last Answer : As transformer is static device with no moving parts, the losses due to friction & windage are completely absent. Hence transformer has efficiency of more than 90%.

Description : Equivalent circuit of transformer

Last Answer : Equivalent Circuit Diagram of Transformer Referred to Primary: V1 -Primary Input voltage I1 - Input Current I0- Exciting current/ No load current Im- Magnetizing component ... equivalent of secondary terminal voltage ZL- Load impedance ZL ′- Primary equivalent of load impedance

Description : Single phase transformer

Last Answer : Single phase Transformer Transformer

Description : What is the use of transformer?

Last Answer : The use of transformer  is to do lower or raise  the voltage or currents in an electrical  circuit.  That's quite so simple. 

Description : Write about transformer on DC.

Last Answer : Transformer on DC : Transformer cannot work on DC. Transformer works on electromagnetic induction principle. Electromagnetic induction principle means when flux linking with coil changes and EMF induced in it ... winding insulation will burn. https://youtu.be/TVp_0fIfxqY

Description : Why phasing out and polarity test is carried out on three phase transformer?

Last Answer : The phasing out test is carried out to identify the windings (primary and secondary) of corresponding phase of the three phase transformer. The polarity test is carried out to identify the ... identical polarity of the primary and secondary windings of each phase of the three phase transformer.

Description : State any four characteristics of core type transformer.

Last Answer : Characteristics of core type transformer: i) It has one window. ii) It has one magnetic circuit. iii) Core surrounds the winding. iv) Average length of core is more. v) Area of cross ... Better cooling for winding. vii) Mechnical strength is comparatively less. viii) Repair and maintenance is easy.

Description : Explain construction and working of single phase Auto transformer.

Last Answer : Construction of single phase auto transformer: (i) It has only one winding wound on a laminated circular magnetic core. (ii) The core is made of silicon steel stampings. (iii) The two terminals of the ... help of handle. 5) The same transformer can be used as step-up or step down auto-transformer

Description : Full load copper loss in a transformer is 1600 watts. At half load the copper loss will be: A) 6400 watt B) 1600 watt C) 800 watt D) 400 watt

Last Answer :  Full load cupper loss in a transformer is 1600 watts. At half load the cupper loss will be: 400 watt

Description : The current transformer that is used to measure a 100 A current by 5 A ammeter is a_____.

Last Answer : The current transformer that is used to measure a 100 A current by 5 A ammeter is a step up transformer

Description : Three phase step-up transformer installed at power house, just before commencement of transmission line, have:

Last Answer : Three phase step-up transformer installed at power house, just before commencement of transmission line, have: star delta connections

Description : When two transformer of different kVA rating are connected in parallel they share the load in proportion to their respective kVA rating only when their:

Last Answer : When two transformer of different kVA rating are connected in parallel they share the load in proportion to their respective kVA rating only when their: P u impedance are equal

Description : The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The secondary output voltage will be (A) 3.6 V. (B) 2.5 V. (C) 3.0 V. (D) 6.0 V.

Last Answer : The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The secondary output voltage will be 3.0 V.

Description : The core flux of a practical transformer with a resistive load  A) Is strictly constant with load changes B) Increases linearly with load C) Increases as the square root of the load D) Decrease with increased load

Last Answer : The core flux of a practical transformer with a resistive load Is strictly constant with load changes

Description : The function of oil in a transformer is to provide  A) Insulation and cooling B) Protection against Lightning C) Protection against short circuit D) Lubrication

Last Answer : The function of oil in a transformer is to provide Insulation and cooling