22 No load test on a transformer is carried out to find
A. copper loss
B. magnetising current
C. Magnetising current and no load loss
D. Efficiency of the transformer

1 Answer

Answer :

C. Magnetising current and no load loss

Related questions

Description : 40 No load test on a transformer is carried out to find A. Copper loss B. magnetising current C. Magnetising current and loss D. Efficiency of the transformer

Last Answer : C. Magnetising current and loss

Last Answer : The magnetising current of a transformer is usually small because it has small air gap.

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

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 : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is

Last Answer : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is 0.707

Description : At full -load of a transformer, the iron loss and copper loss are 3000 W and 4000 W respectively. Then total loss at maximum efficiency is :  (A) 7000 W (B) 6000 W (C) 8000 W (D) 4000 W

Last Answer : At full -load of a transformer, the iron loss and copper loss are 3000 W and 4000 W respectively. Then total loss at maximum efficiency is : 6000 W

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

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.

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 : 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 operates 24 hours day at full -load. It's full -load efficiency is :  (A) equal all day efficiency (B) more than all -day efficiency (C) less than all -day efficiency (D) equal to maximum efficiency

Last Answer : A transformer operates 24 hours day at full -load. It's full -load efficiency is : equal all day efficiency 

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

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

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

Description : 48.During light loads, the transformer efficiency is low because A. Secondary output is low B. Transformer losses are high C. Fixed loss is high in proportion to the output D. Cu loss is small

Last Answer : C. Fixed loss is high in proportion to the output

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.

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.

Last Answer : Primary side is low voltage side and secondary side is high voltage side.

Description : 64)During the short-circuit test on a small transformer the frequency is increased from 50-200Hz. The copper losses will increase by a factor of A. 16 B. 4 C. 1 D. 1/4

Last Answer : A) 16

Description : How much is the no load current of transformer?

Last Answer : No load curent of transformer is 3 to 5% of rated current in transformer.

Description : What are two components of no load current in transformer?

Last Answer : i) IM (Magnetizing/reactive /wattless) current. It magnetizes core ii) Iw (Coreloss/ active/wattful ) current. It supplies hysteresis and eddy current loss and negligible I² R loss.

Description : What are the functions of no-load current in a transformer ?

Last Answer : No-load current produces flux and supplies iron loss and copper loss on no-load.

Description : 62)The no-load current drawn by transformer is usually........percent of the full-load current? A. 0.2 to 0.5 % B. 2 to 5% C. 12 to 15 % D. 20 to 30 %

Last Answer : B) 2 to 5%

Description : The inrush current of a transformer at no load is maximum if the supply voltage is switched on  (1) at peak voltage value (2) at zero voltage value (3) at half voltage value (4) at 0.866 time voltage value

Last Answer : At 0.866 time voltage value

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

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

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

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 : [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 : 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.

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 : 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 : 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 : 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 : 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 : 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 : At what power maximum efficiency of power transformer and distribution transformer is designed

Last Answer : Maximum efficiency of the transformer is attained at certain load factor (α) when core losses of transformer is equal to the copper losses. PCore loss = α ^2 X PCopper loss From the ... the day. Hence distribution transformers are designed to have maximum efficiency at 50% of the rated full load

Description : What are the necessary tests to determine the efficiency, voltage regulation, and temperature rise of winding & insulation of transformer?

Last Answer : 1.Direct loading test 2.Open circuit test 3. Short circuit test 4. Sumpner's or back to back test

Description : Define all day efficiency of a transformer?

Last Answer : A:It is computed on the basis of energy consumed during a certain period, usually a day of 24 hrs. All day efficiency=output in kWh/input in kWh for 24 hrs.

Description : What is the condition for maximum efficiency of transformer?

Last Answer : When Iron losses is equal to copper losses.

Description : Define efficiency of the transformer?

Last Answer : Transformer efficiency ƞ= (output power/input power) x 100

Description : Why the efficiency of distribution transformer is 60 to 70 % and not 100%?

Last Answer : Distribution transformer is designed for maximum efficiency at 60% to 70% load as it normally doesn't operate at full load all the time. Its load depends on distribution demand. Whereas power transformer ... efficiency at 100% load as it always runs at 100% load being near to generating station.

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 : Transformer efficiency

Last Answer : Transformer efficiency

Last Answer : The efficiency of a power transformer is of the order of 98 percent.

Last Answer : In a transformer, routine efficiency depends upon load current and power factor of load.

Last Answer : The maximum efficiency of a distribution transformer is at 50% full load.

Description : The efficiency of a transformer, under heavy loads, is comparatively low because?

Last Answer : The efficiency of a transformer, under heavy loads, is comparatively low because copper loss becomes high in proportion to the output.

Last Answer : The efficiency of transformer is Greater than electrical Machine because there is no rotational losses in transformer and there is no air gap losses in transformer so losses is less in transformer compare to electrical machine so efficiency is higher in case of transformer.