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

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

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

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

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

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

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

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

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

The secondary of a current transformer is always short-circuited under operating conditions becaus Answer : The secondary of a current transformer is always short-circuited under operating conditions because itÂ avoids core saturation and high voltage induction. ...

A transformer operates 24 hours day at full -load. It's full -load efficiency is :Â (A) equal all d Answer : A transformer operates 24 hours day at full -load. It's full -load efficiency is :Â equal all day efficiencyÂ ...

A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 Answer : Please show the solution for this question...

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

The operating point of a protective current transformer is near the Answer : The operating point of a protective current transformer is near theÂ Ankle point ...

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

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

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

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

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

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

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

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

Even at no-load, a transformer draws current from the mains. Why? Answer : Even at no-load, a transformer draws a small amount of current from the mains. This is due to two main reasons: 1. **Magnetizing Current**: To create the magnetic field in the core, the transformer needs a magnetizing current. This current is necessary to establish and maintain the magnetic flux in...

A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred Answer : A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Î© and reactance of 0.5 Î©. The approximate primary induced emf isÂ 226 V ...

Transformer efficiency Answer : Transformer efficiency ...

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....

When secondary of a current transformer is open-circuited its iron core will be? Answer : When secondary of a current transformer is open-circuited its iron core will beÂ hot because of heavy iron losses taking place in it due to high flux density. ...

The inrush current of a transformer at no load is maximum if the supply voltage is switched onÂ (1) Answer : At 0.866 time voltage value...

Answer : In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will beÂ more than full-load current. ...

When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct curren Answer : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30Â°, the displacement power factor of the rectifier isÂ â3/2 ...

In which fault the maximum short circuit current occurs? Answer : In three phase bolted fault the maximum short circuit occurs. ...

A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion o 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 isÂ 0.707 ...

A transformer has negative voltage regulation when its load power factor isÂ Â (1) Zero (2) Unity (3 Answer : Leading...

A zener voltage regulator has load requirements of 12 V and 2 A. The zener diode minimum current req Answer : A zener voltage regulator has load requirements of 12 V and 2 A. The zener diode minimum current requirement is 0.2 A. The minimum voltage at input is 24 V. What is the required value of series resistance with source? A) 5.45 Ω B) 6 Ω C) 7.2 Ω D) 6.38 Ω ...

The sequence components of current of a single-phase load connected to a 3-phase system are (A) equ Answer : The sequence components of current of a single-phase load connected to a 3-phase system areÂ equal positive, negative and zero sequence components ...

Give the circuit analysis of current source inverter with resistive load. What are the main differen Answer : Current source inverter (CSI): In current source inverter, the output current is independent of load. The input current of current source inverter is constant. Current source converter converts DC input current to AC output current. Output AC frequency depends on triggering of SCRs. The input to...

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

Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer againstÂ internal short-circuits. ...

Answer : The full-load copper loss of a transÂŹformer is 1600 W. At half-load, the copper loss will beÂ 400 W. ...

Step-down transformer converts high voltage and low current into:Â (A) How voltage and high current Answer : Step-down transformer converts high voltage and low current into:Â Low voltage and high current ...

In a single-phase transformer, the magnetizing current is (A) in phase with the no-load current (B Answer : In a single-phase transformer, the magnetizing current isÂ in phase with the flux in the core ...

How eddy current is produced in a transformer? Answer : Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the transformer. Here's a simplified explanation of how they are produced: 1. **Changing Magnetic Field**: In a transformer, an alternating current (AC) flowing through the primary coil generates...

For a constant load current, transformer maximum efficiency occurs atÂ Â (a) any power factor (b) ze Answer : For a constant load current, transformer maximum efficiency occurs atÂ unity power factorÂ ...

The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating a Answer : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, Î± and flux, ÎŠÂ directly proportional to Î± and inversely proportional to ÎŠ ...

In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, Î± and with la Answer : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, Î± and with large R-L load, the input source current isÂ alternating rectangular pulses ...

Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power Answer : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency isÂ 50 Hz ...

Answer : In a transformer, routine efficiency depends uponÂ load current andÂ power factor of load. ...

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

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

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

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

Answer : The efficiency of a properly designed synchronous motor will usually fall in rangeÂ 85 to 95%. ...

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