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Transformers and Electrical Energy Transmission

Have you heard about Transformers before? If yes, you might also know the purpose of using transformers. In simple terms, a transformer is a device that controls voltage by either increasing or decreasing it. Transformers are primarily utilized for the transmission of electrical energy. The fundamental operation of a transformer is based on mutual inductance between two circuits that are linked by a common magnetic flux.

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Transformers

A basic transformer comprises two coils that are electrically isolated but magnetically connected through a path of reluctance. The operational concept can be better grasped by referring to the diagram provided above.

Source: Wikipedia

The diagram illustrates an electrical transformer consisting of a primary coil and a secondary coil wound around a soft iron core. The core is laminated to reduce eddy currents. Both coils exhibit high mutual inductance.

A mutual electromotive force is induced in the transformer from the alternating flux generated in the laminated core. This induction is a result of the coil connected to a source of alternating voltage. The majority of the alternating flux generated by this coil is linked with the other coil, thereby creating the mutual induced electromotive force.

Browse more Topics under Alternating Current

• Transformer Operation: Transformers control voltage through mutual inductance between two circuits linked by a magnetic flux.
• Components of a Transformer: A basic transformer consists of a primary coil, a secondary coil, and a soft iron core.
• Mutual Inductance: Both coils in a transformer exhibit high mutual inductance due to their magnetic connection.
• Induced Electromotive Force: The alternating flux in the laminated core induces a mutual electromotive force in the transformer.

Summary of AC Circuits and Transformers

Representation of AC Current and Voltage by Rotating Vectors – Phasors

• Phasors represent AC current and voltage using rotating vectors.

AC Voltage Applied to Different Components

• AC Voltage Applied to a Resistor
• When AC voltage is applied to a resistor, the current is in phase with the voltage.
• AC Voltage Applied to a Capacitor
• When AC voltage is applied to a capacitor, the current leads the voltage by 90 degrees.
• AC Voltage Applied to an Inductor
• When AC voltage is applied to an inductor, the current lags the voltage by 90 degrees.
• AC Voltage Applied to a Series LCR Circuit
• In a series LCR circuit, the current and voltage relationships depend on the values of inductance, capacitance, and resistance.

Power in AC Circuit: The Power Factor

• The power factor in AC circuits indicates the efficiency of power transfer.

LC Oscillations

• LC oscillations occur in circuits with inductors and capacitors, exhibiting oscillatory behavior.

Induced Electromotive Force (EMF)

Electromotive force (EMF) can be understood through Faraday's laws of Electromagnetic Induction:

e = -dΦ/dt

Induced EMF in primary and secondary coils is related by the transformation ratio:

Vp/Vs = Np/Ns

Where Vp is the primary voltage, Vs is the secondary voltage, Np is the number of turns in the primary coil, and Ns is the number of turns in the secondary coil.

Understanding Transformers

Transformers are essential electrical devices that facilitate the transfer of electric power between circuits. There are primarily two types of transformers:

• Step-up Transformer
• Step-down Transformer

A Step-up Transformer functions by converting a low voltage input into a higher voltage output. This occurs when the number of turns in the primary coil (Np) is less than the number of turns in the secondary coil (Ns). For instance, in a step-up transformer, if Np < ns,="" the="" voltage="" is="" />

Conversely, a Step-down Transformer operates by converting a high voltage input, where the current is reduced, into a lower voltage output when the current increases. In this case, the number of turns in the primary coil is more than the number of turns in the secondary coil (Np > Ns).

Transformers carry out their functions through various principles:

• Transfer of electric power from one circuit to another.
• Transfer of electric power without altering the frequency.
• Operation based on the principle of electromagnetic induction.
• Establishing a connection between two electrical circuits through mutual induction.

Electrical Transformers: Key Concepts

Primary and Secondary Windings Relationship

• The number of primary windings is 100, and the secondary windings are 300.
• Given primary voltage: 200V
• To find secondary voltage:
  • Calculate using the transformer formula: \( V_{s} = V_{p} \times \frac{N_{s}}{N_{p}} \)
  • Substitute the values: \( V_{s} = 200 \times \frac{300}{100} = 600V \)

Use of Soft Iron Core in Transformers

• Reason for using a soft iron core:
  • The hysteresis curve of a soft iron core is thin, resulting in minimal energy loss.
  • Using a soft iron core reduces energy loss during the transfer from primary to secondary coils.

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Alternating Current

• Transformers
• LC Oscillations
• Power in AC Circuit: The Power Factor
• AC Voltage Applied to a Series LCR Circuit
• AC Voltage Applied to an Inductor
• AC Voltage Applied to a Capacitor
• Representation of AC Current and Voltage by Rotating Vectors - Phasors

2 responses to "Representation of AC Current and Voltage by Rotating Vectors - Phasors"

• Tanishk says: April 8, 2019 at 3:03 pm - Awesome Reply
• sridhar Dasari says: April 9, 2019 at 9:33 am - Awesome post...

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