what is a transformer ? types of transformers construction , working principle and efficiancy formula
What is a Transformer ?
- A transformer is a electrical device which is used for changing the AC voltages.A transformer which increase the AC voltages is called step up transformer and transformer which increase the AC voltage is called step-up transformer.
- It does this by changing the voltage and current levels while maintaining the frequency of the alternating current (AC) signal, typically to increase (step-up) or decrease (step-down) voltage for purposes such as power distribution, transmission, or voltage matching in electrical systems.
Types of transformer
Based on the voltage levels
There are two type of transformer based on the voltage level are classified follow:
- Step up transformer:
Step up transformer increase the voltage level by adjusting the turns of primary and secondry windings.the primary winding of step up transformer is having lesser turns and secondry winding of a step up transformer have higher turns {if higher turns higher the voltage and lower the current we get at secondry side}.
- Step down transformer :
The primary winding of step up transformer is having higher turns and secondry winding of a step down transformer have lower turns {if lower turns lower the voltage and higher the current we get at secondry side }.
Based on construction:
There are two types of transformer based on construction classified as follow:
Based on core of transformer:
- Air Core Transformer:
The flux linkage between primary and secondary winding is through the air.
Applications: Air-core transformers are designed to transfer radio-frequency currents.
- Iron core transformer:
The flux linkage between primary and secondary winding is through the iron core.
Applications: Iron-core transformers serve analogous functions in the audio-frequency range.
Based on winding arrangement:
- Auto transformer:
Auto transformer has only one common winding act as primary and secondary winding.
Based on Install Location
- Power Transformer:
A power transformer is a fixed device that converts power from one circuit to another without changing the frequency. A transformer is introduced as a static device because there are no moving or rotating components. Power transformers are mainly used at generation side and substations.
- Distribution Transformer:
Distribution transformer are mainly used for domestic purpose and also known as pole mounted transformer it basically convert 11kv to 440v
- Measurement Transformers:
They are mainly used for measuring voltage and current. Eg current transformer and potential transformer.
Construction of a Transformer:
- A transformer consist of a soft iron core made up of laminated sheets , well insulated from eachother. two coil P1,P2 [primary coil] and S1,S2 [secondery coil] are wound on the same core, but are well insulated from eachother.both the coils are insulated from the core.
- The source of altranating emf is connected to the primary coil P1,P2 and a load resistance R is connected to the secondary coil S1,S2.
working principle:
- working principle of transformer is depand on the faraday law of mutual induction . When two coils are brought in proximity to each other, the magnetic field in one of the coils tends to link with the other. This further leads to the generation of voltage in the second coil. This property of a coil which affects or changes the current and voltage in a secondary coil is called mutual inductance.
- According to faraday's law of electromagnetic induction the induced emf per turn is same for both primary and secondary windings.
- Here np and ns repersent total number of turns in the primary and secondary respectively.
- As we assume that no energy is lost along the way, conservation of energy require that:
- If Ns>Np then Es>Ep then the transformer is called step up transformer.
- If Ns<Np then Es<Ep then the transformer is called a step down transformer.
