Emf Equation of Transformer,Turns Ratio of Transformer

EMF Equation of Transformer Turns Voltage Transformation Ratio of Transformer

Emf Equation of Transformer

EMF Equation of transformer can be established in a very easy way. Actually in electrical power transformer, one alternating electrical source is applied to the primary winding and due to this, magnetizing currentflowing through the primary winding which produces alternating flux in the core of transformer. This flux links with both primary and secondary windings. As this flux is alternating in nature, there must be a rate of change of flux. According to Faraday’s law of electromagnetic induction if any coil or conductor links with any changing flux, there must be an induced emf in it. emf equation
As the current source to primary is sinusoidal, the flux induced by it will be also sinusoidal. Hence, the function of flux may be considered as a sine function. Mathematically, the derivative of that function will give a function for the rate of change of flux linkage with respect to time. This latter function will be a cosine function since d(sinθ)/dt = cosθ. So, if we derive the expression for rms value of this cosine wave and multiply it with the number of turns of the winding, we will easily get the expression for RMS value of induced emf of that winding. In this way, we can easily derive the emf equation of transformer.
secondary induced voltage ideal transformer
Let’s say, T is number of turns in a winding,
Φm is the maximum flux in the core in Wb.

As per Faraday’s law of electromagnetic induction,

Where φ is the instantaneous alternating flux and represented as,

As the maximum value of cos2πft is 1, the maximum value of induced emf e is,

To obtain the rms value of induced counter emf, divide this maximum value of e by √2.

This is the EMF equation of transformer.
If E1 & E2 are primary and secondary emfs and T1 & T2 are primary and secondary turns then, voltage ratio or turns ratio of transformer is,

Transformation Ratio of Transformer

This constant is called transformation ratio of transformer , if T2>T1, K > 1, then the transformer is step up transformer. If T2 < T1, K < 1, then the transformer is step down transformer.

Voltage Ratio of Transformer

This above stated ratio is also known asvoltage ratio of transformer if it is expressed as ratio of the primary and secondary voltages of transformer.

Turns Ratio of Transformer

As the voltage in primary and secondary of transformer is directly proportional to the number of turns in the respective winding, the transformation ratio of transformer is sometime expressed in ratio of turns and referred as turnsratio of transformer .

Comments

Auto Transformer: What is it? (Definition, Theory & Diagram)

W hat is an Autotransformer? An autotransformer (or auto transformer ) is a type of electrical transformer with only one winding. The “auto” prefix refers to the single coil acting alone (Greek for “self”) – not to any automatic mechanism. An auto transformer is similar to a two winding transformer but varies in the way the primary and secondary winding of the transformer are interrelated. Autotransformer Theory In an auto transformer, one single winding is used as primary winding as well as secondary winding. But in two windings transformer two different windings are used for primary and secondary purpose. A circuit diagram of auto transformer is shown below. The winding AB of total turns N 1 is considered as primary winding. This winding is tapped from point ′C′ and the portion BC is considered as secondary. Let’s assume the number of turns in between points ′B′ and ′C′ is N 2 . If V 1 voltage is applied across the winding i.e. in between ′A′ and ′C′. Hence, the voltage ...

Shell Type Transformer: What is it? And it's Applications

D epending on the construction of its magnetic core, we can categorize transformers into two types: Shell Type Transformer Core Type Transformer Core of Shell Type Transformer We use ‘E’s and ‘L’s shape laminations to make the core of the shell-type transformer . Limb of Shell Type Transformer The core of a single phase shell type transformer is constructed with of three limbs (legs). This design increases the mechanical strength of the core. It also improves the protection of windings from external mechanical shocks. The HV and LV windings are wound around the central limb. The central limb carries the entire flux (φ), whereas the side limbs carry half of the flux (φ/2). Hence, to accommodate the flux the cross-section of the central limb is twice than that of the side limbs. The magnetic flux flows through two closed magnetic paths which decrease the core losses and hence increase the efficiency of transformer . So, shell type transformer gives more output compared to similar c...

Transformer Construction

Transformer Construction The three main parts of a transformer: Primary Winding of Transformer Magnetic Core of Transformer Secondary Winding of Transformer Primary Winding of Transformer Which produces magnetic flux when it is connected to an electrical source . Magnetic Core of Transformer The magnetic flux produced by the primary winding, that will pass through this low reluctance path linked with secondary winding and create a closed magnetic circuit . Secondary Winding of Transformer The flux, produced by primary winding, passes through the core, will link with the secondary winding. This winding also wounds on the same core and gives the desired output of the transformer .

Electrical engineers

Search This Blog