What is a single phase transformer?

A single-phase transformer is a type of power transformer. It is an electrical device that accepts converts the single phase alternating power into single phase alternating power. In this power conversion the voltage is stepped up or down. If the voltage is stepped up, the current will be stepped down and if the voltage is stepped down, the current will be stepped up.

What is the principle of a single phase transformer?

A transformer is a tool that converts magnetic energy into electrical energy. It contains electrical coils referred to as single-digit curves and secondary curves. The main winding of the transformer receives electricity, as the secondary winding gives you energy. A magnetic circuit called "center" is often used to wrap the coils. The two coils, namely primary coils and secondary coils, are electrically disconnected, but magnetically connected.

The single-phase transformer rate of rotation is defined as the turns ratio of the number of turns in the main winding to the number of turns in the secondary winding.

An electric current passes through the first converter number and forms a magnetic head, which invests in the secondary transformer. Depending on the type of application, a single-phase transformer is used to increase or decrease the output voltage. This converter is usually a very efficient power transformer with occasional losses.

A diagram of single-phase transformers is shown below.

А single segment trаnsfоrmer орerаtes on the рrinсiрle оf Fаrаdаy's Laws оf Eleсtrоmаgnetiс Induсtiоn. Usuаlly  the integrаted inрut аmоng the рrimаry аnd seсоndаry windings is resроnsible fоr the орerаtiоn оf the trаnsfоrmer inside the eleсtriс trаnsfоrmer.

Working of a single-phase transformer

A transformer is a common device that transmits electricity from one circuit to another at the same frequency. It contains basic and secondary windings. This transformer operates on the principle of mutual inductance.

When the primary transformer is connected to an AC source, current flows into the coil producing the magnetic field. This condition is known as mutual inductance, and the current flow follows the Faraday Input Electricity Act.

The Faraday Law of electromagnetic induction, a current that is placed in a magnetic field which is alternating in nature, the conductor will experience a force. In case the conductor circuit is closed then a current is induced in the circuit.

As the current increases from zero to its maximum value, the magnetic field intensifies and is supplied by dɸ/dt. Here, dɸ is the change in flux and dt is the change in time.

This electromagnetic induction creates a magnetic field which extends out to the coil of the transformer and magnetic field. Both the winding are connected to this magnetic field. The force of the magnetic field generated in the context depends on the rotation angle and the current value. Magnetic flux and current are the same.

Construction of a single-phase transformer

A simple single-phase transformer has each cylindrical welded wings on the soft metal part separately to provide the required magnetic circuit, commonly referred to as the "transformer core". It provides a magnetic field flow path to attract secondary voltage between secondary windings—Single-phase transfer, not a delta-wye connection. Star/Delta connections are, in all likelihood, the maximum commonplace decreased secondary voltage starters. Delta-delta or star-star may be used to reduce the beginning current implemented to the motor as a means of lowering the disturbances and interference on the electrical transformers supply.

The secondary windings are not close enough to have an effective magnetic field. Therefore, coupling and increasing the magnetic rotation near the coils can improve the magnetic coating between the primary and secondary windings. Thin steel rods will be used to prevent power loss from the core.

Based on winding, the transformer is divided into two parts:

Core-type transfer

Inside the core-type transformer, a portion of the main phase is protected by windings. Optionally, the main section of the core-type transformer may be rectangular, and the coils can be both rectangular or circular. Each winding is mounted on opposite sides of the middle section.

Any transformer is made up of mainly three parts: total, the first number turns ratio, and the second turn.

The diagram represents the winding of the coil in the core type transformer.
Core type transformer
Creative Commons Attribution-ShareAlike 3.0 | https://commons.wikimedia.org | Spinningspark

The middle element is the main part where it provides a continuous magnetic field with a low air gap. It is made up of steel sheets with plastic strips of high silicon value. And the infused sheets hold an increase in penetration and a slight loss of hysteresis.

To minimize losses by using eddy currents, a sheet metal involves the use of a light-coated core-plate polishing material or a coating layer with an oxide layer on top.

Shell-type transfer

The shape of this transformer is rectangular, and it consists of 3 important parts like one core and two windings. It has two windings, specifically primary winding and secondary winding. The arrangement of these windings can be completed in one limb. The coils of this transformer may be wounded in the form of the multi-layer disc wherein these layers are insulated via paper from each other.

The diagram represents the winding of the coil in a shell type transformer.
Shell type transformer
Creative Commons Attribution-ShareAlike 3.0 | https://commons.wikimedia.org | Spinningspark

High scores, low input voltage, and cooling are not always powerful in this sort of transformer. The winding of a shell-type transformer is distributed type so that the heat is dissipated. This transformer is likewise known as a sandwich in any other disc winding case. Maintaining these transformers is tough and they require excess mechanical power.

Application of a single-phase transformer

Single-phase transformers are extensively used in low voltage applications. The single-phase transformers are frequently used to step down the single section supply 220 volts to decrease voltage. The transformer is used for power delivery to digital gadgets. The transformer is used in the AC or DC voltage rectifier, digital circuits, etc.

The primary use of a transformer is to reduce the secondary voltage of conventional energy circuits to enable the working of low-voltage devices, which include doorbells and toy electric-powered trains. It is also used to elevate the voltage from electric turbines so that electric power can be carried over long distances.

Some other applications:

  • Step-down localized power distribution.
  • TV units to regulate voltage.
  • Low voltage digital devices.
  • Step-up energy in domestic inverters.
  • Non-city areas wherein electrical demands are less.
  • Industrial and home lighting and heating gadget, light-commercial.

Common Mistakes

Note that the symbol of single junction transistor signal looks very similar to the JFET. When one or more transformer works on parallel connection, then the chance of fault occurrence will increase. It is not accurate to apply outdoors. A transformer will not work with DC voltage under any circumstance.

Context and Applications

This subject matter is mandatory for undergraduate and graduate programmes, mainly for:

  • Bachelor of Technology in the Electrical and Electronics Department
  • Bachelor of Science in Physics
  • Master of Science Physics
  • Transformer and its types
  • Step up transformer
  • Step down transformer
  • Hysteresis law

Practice Problems

Q1. A transformer is a tool that converts magnetic energy to __________.

  1. Electrical energy
  2. Electromagnetic energy
  3. Both
  4. None of these

Correct option- (a)

Explanation- A transformer is a tool that converts magnetic energy into electrical energy.

Q2. Single phase transformers are extensively used in ____________ applications.

  1. High voltage
  2. Low voltage
  3. Both
  4. None of these

Correct option- (b)

Explanation- Single-phase transformers are extensively used in low voltage applications. The single-phase transformers are frequently used to step down the single section supply 220 volts to decrease voltage.

Q3.The shape of the shell-type transformer is________.

  1. Square
  2. Triangle
  3. Rectangular
  4. None of these

Correct option- (c)

Explanation-The shape of this transformer is rectangular, and it consists of 3 important parts like one core and windings.

Q4. The shape of core-type transformer is________

  1. Square
  2. Triangle
  3. Rectangular
  4. None of these

Correct option- (c)

Explanation- The core-type transformer is rectangular, and the coils will be both rectangular or circular. Each winding is mounted on opposite sides of the middle section.

Q5. А single segment trаnsfоrmer орerаtes on the рrinсiрle _________.

  1. Fаrаdаy's Law
  2. Thevenin law
  3. Kirchhoff law
  4. None of these

Correct option-(a)

Explanation- А single-segment transformer орerates at the рrinсiрle оf Fаrаdаy's Law оf Eleсtrоmаgnetiс Induсtiоn. 

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