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Answer :

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

Related questions

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 : 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.

Last Answer : Generators for peak load plants are usually designed for maximum efficiency at 50 to 75 percent full load.

Last Answer : Transformer efficiency is maximum when copper losses are equal to iron losses.

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 is one which has no losses and magnetic leakage.

Description : The efficiency of two identical transformers under load conditions can be determined by?

Last Answer : The efficiency of two identical transformers under load conditions can be determined by back-to-back test.

Description : If a transformer is continuously operated the maximum temperature rise will occur in?

Last Answer : If a transformer is continuously operated the maximum temperature rise will occur in windings.

Last Answer : D.C. generators are normally designed for maximum efficiency around full-load.

Last Answer : The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.

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%.

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

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.

Description : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?

Last Answer : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.

Description : The synchronous motor will develop maximum power when the load angle is?

Last Answer : The synchronous motor will develop maximum power when the load angle is 900.

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 : 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 : 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 : Transformer efficiency

Last Answer : Transformer efficiency

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.

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 : A transformer has negative voltage regulation when its load power factor is   (1) Zero (2) Unity (3) Leading (4) Lagging

Last Answer : 0

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

Description : A network contains linear resistors and ideal voltage sources. If values of all the resistors are doubled then the voltage across each resistor will

Last Answer : A network contains linear resistors and ideal voltage sources. If values of all the resistors are doubled then the voltage across each resistor will not change

Description : The internal resistances of an ideal current source, and an ideal voltage source are, respectively, (A) 0, ∞ (B) ∞, ∞ (C) ∞, 0 (D) 0,0

Last Answer : The internal resistances of an ideal current source, and an ideal voltage source are, respectively, ∞, 0

Description : The gain of an ideal amplifier must be

Last Answer : The gain of an ideal amplifier must be infinity

Description : An ideal voltage source has?

Last Answer : An ideal voltage source has zero internal resistance.

Description : An ideal voltage source should have?

Last Answer : An ideal voltage source should have zero source resistance.

Last Answer : An ideal traction system should have easy speed control, high starting tractive effort, equipment capable of with standing large temporary loads.

Last Answer : For any type of consumer the ideal tariff is three part tariff.

Description : What should be the ideal resistance of ammeter ?

Last Answer : Ideal resistance of ammeter should be zero.

Description : What are the desirable characteristics of ideal switch?

Last Answer : Desirable characteristics of the ideal switch: It is desirable to have power switches characteristics closer to ideal switch. The ideal switch should have the following characteristics. Zero resistance when ... . 100% efficiency. Able to control power flow with zero power dissipation.

Description : what is ideal voltage source?

Last Answer : every voltage source have their own resistance that is called as internal resistance it is because of the resistance of electrodes and electrolytes in the battery interms of other supplyit have ... in universe it means ideal voltage source is this voltage source having internal resistance zero

Description : Negative voltage regulation is indicative that the load is?

Last Answer : Negative voltage regulation is indicative that the load is capacitive.

Description : Minimum voltage regulation occurs when the power factor of the load is?

Last Answer : Minimum voltage regulation occurs when the power factor of the load is leading.

Last Answer : An ideal transformer has infinite values of primary and secondary inductances. The statement is false.

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

Description : "Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with?

Last Answer : "Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load". The above statement is associated with Maximum power transfer theorem.

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.

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 : 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.

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

Description : 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

Last Answer : C. Magnetising current and no load loss

Description : Define : i) Maximum Value ii) RMS Value of ac supply

Last Answer : i) Maximum Value :- The maximum or peak value attained by an alternating quantity during positive or negative half cycle, is called maximum value or peak value.  ii) RMS Value of ac ... as produced by the alternating current when flowing through the same resistance and for the same time. 

Description : Define the following terms: 1) Virtual height 2) Actual height 3) Critical frequency. 4) Maximum usable frequency.

Last Answer : 1) Virtual height:- The incident and refracted rays follow paths that are exactly the same as they have been if reflection had taken place from a surface located at a greater height, called ... angle of incidence is other than the normal is known as maximum unstable frequency. MUF= fc secθ 

Description : Maximum Power Transfer Theorem 1

Last Answer : Maximum Power Transfer Theorem 1

Description : State maximum power transfer theorem for DC circuit.

Last Answer : Maximum power transfer theorem for DC circuit: The maximum power transfer theorem states that the source or a network transfers maximum power to load only when the load resistance is equal ... removed (disconnected) ii) All internal independent sources are replaced by their internal resistances.

Description :  An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when A) ZL = R B) ZL = jXS C) ZL = R-jXS D) ZL = R+jXS 

Last Answer :  An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when ZL = R-jXS