The main reason for generation of harmonics in a transformer could be saturation of core.
Explain the effect of Harmonics on the Transformer.
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.
Harmonics in transformer result in increased core losses, increased I2R losses, and magnetic interference with communication circuits.
What are the main causes of harmonics?
Harmonic is a non linear load because linear load voltage deviated due to connection of some electrinie device such as converter,inverter
State the need for reduction of harmonics in inverters. Enlist the various methods for reduction of harmonics in inverter output.
Slot harmonics are reduced in induction motors by using (A) fractional-pitch windings (B) fractional-slot windings (C) integral-slot windings (D) distributed windings
Slot harmonics are reduced in induction motors by using fractional-slot windings
Why harmonics are generated in electrical system?
What is mitigation of harmonics?
What is current harmonics?
What are even and odd harmonics?
Why do non linear loads cause harmonics?
In a transformer the resistance between its primary and secondary should be?
In a transformer the resistance between its primary and secondary should be infinity.
A transformer oil must be free from moisture.
The full-load copper loss of a trans¬former is 1600 W. At half-load, the copper loss will be 400 W.
Iron loss of a transformer can be measured by low power factor wattmeter.
When secondary of a current transformer is open-circuited its iron core will be?
When secondary of a current transformer is open-circuited its iron core will be hot because of heavy iron losses taking place in it due to high flux density.
In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are?
In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are hysteresis and eddy current losses.
The dielectric strength of transformer oil is expected to be?
The dielectric strength of transformer oil is expected to be 33 kV.
The chemical used in breather for transformer should have the quality of cleansing the transformer oil.
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 at unity power factor.
Material used for construction of transformer core is usually silicon steel.
The main purpose of using core in a transformer is to (A) decrease iron losses (B) eliminate magnetic hysteresis (C) reduce reluctance of the common magnetic circuit (D) prevent eddy current loss
The main purpose of using core in a transformer is to reduce reluctance of the common magnetic circuit
No-load current in a transformer lags behind the voltage by about 75°.
The purpose of providing an iron core in a transformer is to decrease the reluctance of the magnetic path.
High voltage winding in a transformer has more number of turns.
The no load current in a transformer lags behind the applied voltage by an angle of about 75°.
In a transformer, routine efficiency depends upon load current and power factor of load.
The purpose of providing iron core in a step-up transformer is to decrease the magnitude of magnetizing current.
In a transformer, the tappings are generally provided on low voltage side.
The thickness of laminations used in a transformer is usually 0.4 mm to 0.5 mm.
conservator or a reservoir tank for insulating oil in transformer which used for balanced the onload oil level with help of oil level indicator which mount on middle part of reservoir tank.
The leakage flux in a transformer depends upon load current.
Noise level test in a transformer is a type test.
The value of flux involved in the e.m.f. equation of a transformer is maximum value.
The function of breather in a transformer is to arrest flow of moisture when outside air enters the transformer.
In a power or distribution transformer about 10 percent end turns are heavily insulated to withstand the high voltage drop due to line surge produced by the shunting capacitance of the end turns.
If a transformer is continuously operated the maximum temperature rise will occur in?
If a transformer is continuously operated the maximum temperature rise will occur in windings.
The hum in a transformer is mainly attributed to?
The hum in a transformer is mainly attributed to magnetostriction.
In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of?
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 path of magnetic flux in a transformer should have?
The path of magnetic flux in a transformer should have low reluctance.
In the transformer low voltage winding has got more cross-sectional area.
Transformer breaths in when load on it decreases.
The use of higher flux density in the transformer design reduces weight per kVA.
The transformer ratings are usually expressed in terms of kVA.
The core used in high frequency transformer is usually air core .
In an actual transformer the iron loss remains practically constant from no load to full load because core flux remains practically constant.
Sandwich type winding is used in 3 phase shell-type transformer.
Reduction in core losses and increase in permeability are obtained with transformer employing?
Reduction in core losses and increase in permeability are obtained with transformer employing core built-up of laminations of cold rolled grain oriented steel.
what do not change in transformer?
Frequency and power are constant in transformers. Suppose we apply 50 Hz input frequency then the output frequency will also be 50 Hz whether the transformer is step up or step down. Similar ... is decreased on secondary side and hence power on primary side and secondary side remains constant.
State why a transformer always have an efficiency of more than 90%.
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%.
Even at no-load, a transformer draws current from the mains. Why?