Which losses in a transformer varies significantly with load

Which losses in a transformer varies significantly with load 

a. Hysteresis losses b. Eddy current losses c. Copper losses d. Core losses 
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Answer :

Which losses in a transformer varies significantly with load Copper losses

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Related questions

A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage

Description : A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is  (A) 50.0% (B) 70.7% (C) 141.4% (D) 200.0%

Last Answer : A 500 kVA, 3-phase transformer has iron losses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is 70.7%

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

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.

The hysteresis and eddy current losses of a single phase transformer working on 200 V, 50 Hz

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

Reduction in core losses and increase in permeability are obtained with transformer employing?

Description : Reduction in core losses and increase in permeability are obtained with transformer employing?

Last Answer : Reduction in core losses and increase in permeability are obtained with transformer employing core built-up of laminations of cold rolled grain oriented steel.

Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is?

Description : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is?

Last Answer : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is approximately equal to 1.

In a synchronous motor which losses varies with load?

Description : In a synchronous motor which losses varies with load?

Last Answer : In a synchronous motor, copper losses varies with load.

Full load copper loss in a transformer is 1600 watts. At half load the copper loss will be:

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

When two transformer of different kVA rating are connected in parallel they share the load in proportion to

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

The core flux of a practical transformer with a resistive load

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

A single-phase transformer has a turns ratio of 1 :2 and is connected to a purely resistive load as shown in the

Description : A single-phase transformer has a turns ratio of 1 :2 and is connected to a purely resistive load as shown in the figure. The magnetizing current drawn is 1A, and the secondary current is 1A. Ifcore losses and ... reactances are neglected, the primary current is  A)1.41A B)2A C) 2.24A D)3A

Last Answer : A single-phase transformer has a turns ratio of 1 :2 and is connected to a purely resistive load as shown in the figure. The magnetizing current drawn is 1A, and the secondary current is 1A. Ifcore losses and leakage reactances are neglected, the primary current is 2.24A

A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at

Description : A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is  (A) 86.7% (B) 88.26% (C) 88.9% (D) 87.8%

Last Answer : A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is 87.8%

A single-phase, 50 kVA, 250 V/500 V two winding transformer has an efficiency of 95% at full load, unity

Description : A single-phase, 50 kVA, 250 V/500 V two winding transformer has an efficiency of 95% at full load, unity power factor. If it is re-configured as a 500 V/750 V auto-transformer, its efficiency at its new rated load at unity power factor will be  (A) 95.752% (B) 97.851% (C) 98.276% (D) 99.241%

Last Answer : A

A single-phase transformer has no-load loss of 64 W, as obtained from an open circuit test. When a short-circuit

Description : A single-phase transformer has no-load loss of 64 W, as obtained from an open circuit test. When a short-circuit test is performed on it with 90% of the rated currents flowing in its both LV and HV windings, ... .0% of the rated current (C) 80.0% of the rated current (D) 88.8% of the rated current

Last Answer : A single-phase transformer has no-load loss of 64 W, as obtained from an open circuit test. When a short-circuit test is performed on it with 90% of the rated currents flowing in its both ... measured loss is 81 W. The transformer has maximum efficiency when operated at 80.0% of the rated current

For a constant load current, transformer maximum efficiency occurs at

Description : For a constant load current, transformer maximum efficiency occurs at   (a) any power factor (b) zero power factor leading (c) zero power factor lagging (d) unity power factor 

Last Answer : For a constant load current, transformer maximum efficiency occurs at unity power factor 

In a transformer, zero voltage regulation at full load is

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 

The no-load current drawn by transformer is usually what per cent of the full-load current ?

Description :  The no-load current drawn by transformer is usually what per cent of the full-load current ?

Last Answer : 5 to 8 percentage of full load current

No-load current in a transformer?

Last Answer : No-load current in a transformer lags behind the voltage by about 75°.

The no load current in a transformer lags behind the applied voltage by an angle of about?

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

No-load current of a transformer has?

Last Answer : No-load current of a transformer has small magnitude and low power factor.

The full-load copper loss of a transformer is 1600 W At half-load, the copper loss will be?

Last Answer : The full-load copper loss of a trans¬former is 1600 W. At half-load, the copper loss will be 400 W.

In an actual transformer the iron loss remains practically constant from no load to full load because?

Description : In an actual transformer the iron loss remains practically constant from no load to full load because?

Last Answer : In an actual transformer the iron loss remains practically constant from no load to full load because core flux remains practically constant.

An ideal transformer will have maximum efficiency at a load such that?

Last Answer : An ideal transformer will have maximum efficiency at a load such that copper loss equal to iron loss.

For a transformer, operating at constant load current, maximum efficiency will occur at?

Description : For a transformer, operating at constant load current, maximum efficiency will occur at?

Last Answer : For a transformer, operating at constant load current, maximum efficiency will occur at unity power factor.

The maximum load that a power transformer can carry is limited by its?

Description : The maximum load that a power transformer can carry is limited by its?

Last Answer : The maximum load that a power transformer can carry is limited by its voltage ratio.

A no-load test is performed on a transformer to determine?

Description : A no-load test is performed on a transformer to determine?

Last Answer : A no-load test is performed on a transformer to determine magnetizing current and loss.

In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of?

Description : In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of?

Last Answer : In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of less than 15A.

During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Description : During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Last Answer : C) the voltage applied on primary side is low

During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Description : During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer

Last Answer : C) the voltage applied on primary side is low

A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -

Description :  A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  a) 16/9 b) 4 / 3 c) 3/4 d) 9 /16

Last Answer :  A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  9 /16

Which of the following are constant losses in Transformers?

Description : Which of the following are constant losses in Transformers? (1) Winding losses (2) Core losses (3) Both Winding & core losses (4) None of these

Last Answer : Which of the following are constant losses in Transformers? (1) Winding losses (2) Core losses (3) Both Winding & core losses (4) None of these

During short circuit test iron losses are negligible because?

Description : During short circuit test iron losses are negligible because?

Last Answer : During short circuit test iron losses are negligible because the voltage applied on primary side is low.

Losses which occur in rotating electric machines and do not occur in transformers are?

Description : Losses which occur in rotating electric machines and do not occur in transformers are?

Last Answer : Friction losses windage losses 

If the energy input is significantly reduced to the prime mover of one shipboard alternator operating in parallel with others, that alternator will _____________. A. continue to operate at no load B. lose its load and overspeed C. begin to motorize and then trip out D. slow down and operate at reduced load

Description : If the energy input is significantly reduced to the prime mover of one shipboard alternator operating in parallel with others, that alternator will _____________. A. continue to operate at no load B. lose ... overspeed C. begin to motorize and then trip out D. slow down and operate at reduced load

Last Answer : Answer: C

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

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:   

Explain the effect of Harmonics on the Transformer.

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.

List two special feature of welding transformer.

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

State two applications of isolation transformer

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.

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

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%.

Equivalent circuit of transformer

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

Single phase transformer

Description : Single phase transformer

Last Answer : Single phase Transformer Transformer

What is the use of 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. 

Transformer on DC

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

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

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.

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

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.

State any four characteristics of core type 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.

Explain construction and working of single phase Auto transformer.

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

If the frequency of input voltage of a transformer is increased keeping the magnitude of voltage unchanged,

Description :  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) ... current loss will increase D) hysteresis loss will decrease but eddy current loss will remain unchanged

Last 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

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

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

The voltage applied to the H.V. side of a transformer during S.C. test is 2% of the rated voltage. The core loss

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%

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

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