What Is Single Phase Transformer?

     

    A single phase transformer is a device that changes the voltage of electricity in a single-phase AC circuit. It has two coils, one connected to the power source and the other connected to the device using the power. The coils are wrapped around a magnetic core, which helps transfer energy between them safely and efficiently.

    Construction of Single Phase Transformer

     

    A single phase transformer is a high-efficiency piece of electrical equipment, and its losses are very low because there isn’t any mechanical friction involved in its operation.

    Transformers are used in almost all electrical systems from low voltage up to the highest voltage level. It operates only with alternating current (AC) because direct current (DC) does not create any electromagnetic induction.

    The key components of a single phase transformer are:

    Core:
    It is made up of grain-oriented silicon steel laminations to reduce eddy current losses. The core provides a low reluctance path for the magnetic flux.

    Primary Winding:
    It is connected to the source of alternating supply. The number of turns in the primary winding is kept as minimum as possible to reduce copper losses.

    Secondary Winding:
    It is connected to the load. The number of turns is adjusted to get the required output voltage value from the induced EMF.

     

    Working Principle Of Single Phase Transformer

     

    Principle of operation of single phase transformer:

    As an alternating current flows through the primary winding, it produces an alternating magnetic flux φ in the core. According to Faraday’s law of induction, this changing flux induces an EMF (ε) in the secondary winding given by E = -N dφ/dt. 

    The induced EMF causes current to flow in the closed secondary circuit to power the load. The transformer works on the principle of mutual inductance between the two windings.

    Advantages of Single Phase Transformer

    • Simple and robust construction
    • High reliability
    • Nearly sinusoidal voltages and currents
    • Flexible voltage ratios

    Disadvantages of Single Phase Transformer

    • Large size due to one coil per phase
    • Unbalanced currents in 3-wire system
    • Lower efficiency compared to 3-phase transformers

    Applications of Single Phase Transformer

    • Domestic power supply – Step down distribution
    • Welding transformers
    • Battery chargers
    • Small industrial drives
    • UPS systems
    • Street lighting
    • Electric railway traction systems