Types of Transformer

There are various types of transformer based on its parameters and transformer change value of voltage and current ,frequency will not be changed.

Transformer is a device which works on mutual inductance principle to convert electrical energy from one voltage/ current level to another level.

Types of transformer according to supply

Single phase transformer 

  • Single phase transformer is a static device which transfer alternator current A.C power from one circuit to other circuit and in that only used single phase.

Types of Transformer

Three phase transformer :

  • Three phase transformer is mostly used in the power system. This transformer change voltage one circuit to other circuit. Its size a big compared to single phase transformer

Types of  according to construction


Types of Transformer
Core Type and Shell Type

Shell type transformer

  • Shell types of transformer is rectangular form of the coil and this core surrounded the winding as shown in figure, In shell type two parallel magnet path into which the flux in the central limb divided .

Core type transformer

  • A core type of transformer is one in which there is only one iron path. Usually in rectangular form and the winding are wound on two opposite limbs .
  • The magnetic circuit of a core type transformer.the core is made up of silicon steel lamination which one either rectangular of L- shape.

Types of the transformer according to output voltage

Step Up transformer

step up transformer

  • Step up transformer is stepping up value of voltage one circuit to other circuit mean that step up voltage primary to secondary of transformer.We can get high voltage value from secondary site of transformer.
  • Example. 44OV/11KV , 11kv/ 33kv , 33kv/66kv

Step down transformer

step down transformer

  • Step down transformer is stepping down value of voltage one circuit to other circuit mean that step down voltage primary to secondary of transformer.We can get low voltage value from secondary site of transformer.
  • Example. 33kv/11KV , 11kv/ 440v , 66kv/33kv

Types of the transformer according to KVA rating

power transformer

Power transformers are generally used in whole transmission network for stepping up or down the voltage range . power transformer operates mainly during high or peak loads and it has maximum efficiency at or near full load.

This transformar usually will be rating their application (400 kV, 200 kV, 110 kV, 66 kV, 33kV) and are generally rated above 200MVA.

Distribution transformer

  • Distribution Transformers​ steps down the voltage for distribution purpose to domestic or commercial users and you can get only voltage range 440v with three phase and if need 220-250v that time use one phase and neutral (Star connection will be secondary site ) point from secondary site of transformer
  • It has good voltage regulation in power system and it operates 24 hrs a day with maximum efficiency at 50% of full load.

Types of transformer according to mounting

Pole mounted


  • Pole mounted transformers are electric distribution transformers and that are mounted on an electrical service pole (fixed on wood or concrete) and are usually at the level of the overhead cables.



  • The purpose of a substation is to stepping down high voltage electricity from the transmission system to lower voltage electricity so it can be easily distributed or supplied to consumer homes and businesses through distribution lines.

Types of transformer according to different application

Pulse transformer

Image credit : indiamart.com

  • Pulse transformer design for usually finding to minimize voltage drop, rise time,and pulse distortion.
  • Drop is the decline of the output pulse voltage over the duration of one pulse. It is due to magnetizing current increasing during the time duration of the pulse.
  • Pulse transformer is a special type of transformer electrical , it used for electrical isolation between two different circuits.

Grounding Transformer

  • Grounding transformers are typically used to provide a relatively low-impedance path to ground and there by maintaining the system neutral at ground or near ground potential.
  • Its limit the magnitude of transient over voltages in the system when restriking ground faults occur.
  • Its provide a source of ground fault current during line-to-ground this one type of unsymmetrical faults

Capacitive Voltage Transformer

Image credit: https://www.directindustry.com/

  • A capacitor voltage transformer short form is CVT and this is a transformer used in the power systems for step down extra high voltage (EHV) signals to it provides to us a low voltage signal and for metering or operating a protective relay in the system.

Audio frequency transformer

  • Audio Transformers are designed for the purpose of use in the amplifier and high frequency audio and voice circuits for coupling and impedance matching applications

Current transformer

  • These transformers are step up transformer or we can say that current transformer step up the value of voltage from primary to secondary .
  • Hence according to transformation ratio the current will reduce from secondary.
  • And keep mind current point of view ,these are step down transformers which step down the current from primary to secondary.
  • Always asked most top question about CT , click here

Voltage transformer

  • The voltage transformer steps down the high voltage of the line to a level safe enough for the connecting relaying system and its personnel to handle And voltage transformer also called potential transformer.
  • The secondary voltage between line means that line to line basis is 110 V. This helps in standardizing the protective relaying equipment respective of the value of the primary EHV( Extra High Voltage) adopted.
  • A potential transformer primary is connected in parallel at the point where a measurement is a requirement , unlike a Current Transformer whose primary is in series with the line in which current is to be measured.

Welding transformer

  • Welding transformer is stepping up current value and stepping down voltage value.
  • This transformer used for the welding purpose due to we need high current in initial and running condition for produce for arc.

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