what is an isolation transformer and what are its advantages

What is a Transformer

Transformers are used in a power system that is capable to step up the power generated at low voltages to extra high voltages for transmission over long distances and then it could be transformed at low voltages In order to utilize it at load centers. It can transform power from one circuit to others by stepping up or down the primary voltage without any change in frequency. Current in the primary winding will create a varying magnetic flux in the transformer’s core and thus it will create a varying magnetic field in the secondary windings and this is done by mutual inductance

What is an Isolation transformer

An isolation transformer is a kind of current transformer which is used to supply power to equipment. It is not used to increase or decrease the voltage, they are used for other purposes like breaking a circuit into a primary and a secondary, so direct current noise can’t get through, it can prevent capacitance build-up by high-frequency noise, it also prevents unconditional ground connection between the primary and secondary and thus prevents high voltage discharge. It can provide galvanic isolation to the electrical system. Any transformer which is used to transfer signals or power is isolating because the primary or secondary is not connected by conductors instead of that it is done by induction. The transformers which have its main function to isolate circuits can be called as isolation transformers. In isolation transformer, the primary voltage value will be equal to the secondary voltage and the two windings will have the same number of turns to compensate for losses.


What is a three-phase isolation transformer

A three-phase isolation transformer is a 3-phase transformer, they have isolated primary and secondary windings. So the power input will be isolated from the power output. 3-phase isolation transformer has 3 primary and secondary windings that are separated from each other and these windings are insulated from each other. A shielded 3-phase transformer is more efficient than the 3-phase isolation transformer because it can provide protection for sensitive equipment. When more than one shielded 3-phase isolation transformer is installed between the source and the load, it is called as cascading and improves power quality.

What is the difference between transformer and isolation transformer

A transformer is used in a power system to increase and decrease the voltage, for the distribution of the electrical current. While an isolation transformer is not used to increase or decrease the voltage they are used to breaking a circuit into a primary and a secondary, so direct current noise can’t get through. Isolation transformers has symmetrical windings which is meant to decouple two circuits. Isolation transformer helps an AC signal or power to be taken from any device and fed into another without electrically connecting the two circuits. It can also block the transmission of DC signals from one circuit to the other. Isolating transformer isolates the device or equipment from the power supply for safety purposes.

What is a shielded isolation transformer

A shielded isolation transformer has all the features of standard isolation transformer but they have a full copper or aluminum shielding between the primary and the secondary windings. Shielded isolation transformers isolate electrical power from the normal power supply source to reduce the effects of power surges. They are available with electrostatic shields between the primary and secondary to reduce the interference.

Where is isolation transformer used

Isolation transformers are used in a variety of electronic systems to meet safety requirements. Some of them are medical diagnostic equipment, computer systems, and telecommunications equipment. It also helps to reduce the size and cost of power electronic components.

How to do double isolation

Double isolation can be done by putting a metallic safety shield between the primary and the secondary windings and then connecting it to the ground. So the electricity will flow to the ground in case of isolation damage and thus provides safety. Another method of double isolation is by using reinforced insulation and this type of insulation is made up of multiple layers, so if one layer breaks the next layer will provide required safety.

What are the applications of an isolation transformer

  • It can be used in sensitive equipment as power supply
  • Machine or equipment can be isolated from the rest of the electrical installation with the help of the isolation transformer, so power loss can be avoided during installation fault.
  • An isolation transformer can be used to create a star point in grids that do not have such a point
  • Appliances induce a high level of interference back to their power supply if the equipment needs to be protected from this noise isolation transformer can be used for their supply
  • Equipment can be protected from power disturbances like voltage transients, spikes, from DC leakage…
  • It can be used in sensitive equipment, to provide an isolated neutral ground
  • High noise attenuation level even in high-frequency applications
  • Reduced coupling capacitance
  • Suitable for higher harmonic area installation
  • Longer life of the transformer because of less heat dissipation, it can be used as medical transformers
  • It will be useful to protect the patient and operator from electric shock
  • protects the equipment from faulty components or power surges
  • It provides a safer patient environment by reducing the potential hazards and by ensuring that under single fault condition there is still the continuity of supply

What are the advantages of an isolation transformer

  • It can be used to protect people against the dangers of electric shocks
  • It can block the transmission of the DC signal from one circuit to the other and allows AC signals to pass
  • It can block interference caused by ground loops
  • Isolation transformers with an electrostatic shield can be used for the power supplies of sensitive equipment
  • They are used in electronic testing and servicing as a power transformer for safety
  • They are used for power supply of the devices which are not at ground potential
  • It can reduce earth leakage in equipment used in wet locations


News Reporter
post-graduate in Electronics & communication