The voltage transformation ratio of a transformer is equal to the ratio of secondary induced e.m.f. to primary induced e.m.f.

Define: 1) voltage ratio, 2) current ratio, 3) transformation ratio of transformer. Answer : 1) Voltage ratio: The voltages in primary and secondary winding is proportional to number of turns in primary and secondary respectively. So, the voltage ratio is same as transformation ratio. V2/V1 = N2/N1 = K If the number of turns of secondary winding (i.e. N2) is more than number...

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

Use of auto-transformer is economical when the transformation ratio is? Answer : Use of auto-transformer is economical when the transformation ratio is near unity. ...

What is transformation ratio? Answer : Transformation Ratio (k):- It is the ratio of secondary number of turns to primary number of turns. OR It is the ratio of secondary voltage to primary voltage. OR It is the ratio of primary current to secondary current. ...

Source transformation Replace the circuit with voltage source in series with a single resistor Answer : Source transformation Replace the circuit with voltage source in series with a single resistor ...

Source transformation voltage source to current source and vice versa

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 are hysteresis and eddy current losses. ...

A good voltage regulation of a transformer means? Answer : A good voltage regulation of a transformer means output voltage fluctuation from no load to full load is least. ...

If a transformer is switched on to a voltage more than the rated voltage? Answer : If a transformer is switched on to a voltage more than the rated voltage its power factor will deteriorate. ...

Voltage ratio Answer : Voltage ratio ...

A dc chopper is fed from a constant voltage mains the duty ratio of chopper is progressively increa Answer : A dc chopper is fed from a constant voltage mains the duty ratio of chopper is progressively increased while the chopper feeds an RL load. The per unit current ripple would increase to a maximum value at α = 0.5 and then decrease ...

Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5. ...

Find power delivered by voltage source Answer : Find power delivered by voltage source ...

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

The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : (A) 34. Answer : The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : 34.64 kVA ...

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

What is a capacitor voltage transformer? A) It is a transformer used in power systems to step up lo Answer : What is a capacitor voltage transformer? A) It is a transformer used in power systems to step up low voltage signals and provide extra high voltage B) It is a transformer used in power systems to step up high voltage signals and provide extra high voltage C) It is a transformer used in power ...

What is impulse voltage of transformer?

Answer : yes High Voltage side of Transformer winding have more number of turns. and low voltage side of Transformer winding have less number of turns....

Source transformation problem solution Answer : Sure, I can help you with a source transformation problem. Source transformation is a technique used in circuit analysis to convert a voltage source in series with a resistor into an equivalent current source in parallel with a resistor, or vice versa. Here's a step-by-step guide to solve a typical...

Find the current through 4 ohm resistor by source transformation Answer : To find the current through a 4-ohm resistor using source transformation, follow these steps: ### Source Transformation Steps 1. **Identify the Source and Resistor Configuration:** Let's say you have a circuit with a voltage source \( V \) in series with a resistor \( R_s \), and you want to fi...

Wye Delta Transformation Answer : Wye Delta Transformation 1 : https://youtu.be/mPKeczDWZCo Wye Delta Transformation 2 : https://youtu.be/k80VbHI-wwg Wye Delta Transformation 3 : https://youtu.be/6cnwj15uw5M Wye Delta Transformation 4 : https://youtu.be/g0w4Fs09Do4 Wye Delta Transformation 5 : https://youtu.be/GY7L_ixeXPE Wye D...

Explain space vector transformation and space vector switching with the help of diagram. What are th

The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to : Answer : The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to : Z (p.u) ...

State and justify which of the following two transformers is better: Transformer A = 4% voltage re 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 kept constant. Ideally the secondary voltage should remain constant in spite of change in l...

Answer : A transformer cannot raise or lower the voltage of a D.C. supply because Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero. ...

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

Answer : When a given transformer is run at its rated voltage but reduced frequency, its core flux density is increased. ...

Explain the effect of Harmonics on the Transformer. 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 harmonic present in supply voltage. 2. Copper loss: Harmonic current increases copper loss. The loss mainly depends on...

List two special feature of welding transformer. 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 secondary turns. iii) The secondary current is quite high. iv) The secondary has...

State two applications of isolation transformer 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%. 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 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 of no load current Iw-Working component of no load current R0- Core loss resistance X0- magnetizing reacta...

Single phase transformer Answer : Single phase Transformer Transformer ...

What is the use of transformer? Answer : The use of transformer is to do lower or raise the voltage or currents in an electrical circuit. That's quite so simple. ...

Write about transformer on DC. 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. Suppose we give DC to a transformer then DC will set constant magnetic field ...

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...

State any four characteristics of core type transformer. 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 section is less so more turns are required. vi) Better cooling for winding. vii) Mechnical strength is comparatively ...

Explain construction and working of single phase Auto transformer. 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 winging are connected to the supply. (iv) A variable point on the winding is connected to a carbon...

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

Answer : The purpose of providing an iron core in a transformer is to decrease the reluctance of the magnetic path. ...

Answer : In the transformer low voltage winding has got more cross-sectional area. ...

Answer : Primary winding of a transformer could either be a low voltage or high voltage winding. ...

Answer : High voltage winding in a transformer has more number of turns. ...

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

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

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

Answer : Transformer breaths in when load on it decreases. ...

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

Answer : The purpose of providing iron core in a step-up transformer is to decrease the magnitude of magnetizing current. ...

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