Instrument transformers – Definition, types and connection

What is an instrument transformer? Instrument transformers are current and voltage transformation devices that are used to step down the transmission and distribution line voltages and currents to levels that can safely operate measuring instruments, protection devices and control relays by isolating it from the supply voltages. The above diagram shows the basic usage of … Read more

Difference between current transformers and Potential transformers

Current transformers (CT) and Potential Transformers (PT) are instrument transformer types used to step down transmission or distribution line voltages and current to the level that can be measured using measurement devices or controlled using control devices. The principle of operation of a certain type of CT and PT is similar to power transformers. Here … Read more

Potential transformers | Voltage transformers (PT)

Potential transformers (PT) or voltage transformers are instrument transformers used for voltage measurements. They are connected in parallel to the line and operates under the same principle of power transformers. They cannot be used used to supply raw power to the loads. They have an accurate voltage ratio and phase relationship between primary and secondary … Read more

Current transformers (CT)- working, types and connection

What is a current transformer? A current transformer is a type of instrument, used to measure or sense large alternating currents by scaling it to a smaller, safer and measurable value. It transforms the primary current to a proportional secondary value in terms of magnitude and phase. Current transformers are available in various sizes and … Read more

Transformer losses – Load losses and No-load losses

Some amount of power is lost during the voltage transformation process in a transformer. The current flows in a transformer winding and the alternating magnetic field in the core contributes to the majority of transformer losses.

EMF equation of transformers

EMF equation of transformers lets you calculate the RMS values of induced voltages in the primary and secondary windings of a transformer. An alternating voltage, when applied to the primary of a transformer, produces an alternating magnetic field which induces EMF in the secondary windings. The produced magnetic flux is alternating in nature and lags … Read more

Comparison of core type and shell type transformers

A magnetic core and windings are two basic parts of a transformer. The windings are wound over the core and the core encircles the windings. Based on the way the core and the winding are made, transformers are classified into two types: Core type and shell type transformers. Both of them refers to the arrangement … Read more

Selection and sizing of transformers – made easy

A transformer is the device that makes power systems flexible, scalable and help save cost by reducing power loss. Here you can learn the selection and sizing of transformers and code & standards related to transformers. Transformer Nameplate Selection and sizing of a transformer is the process of determining the basic transformer parameters such kVA, … Read more

Autotransformer – Principle, advantages, copper savings

An autotransformer is a single-winding electrical transformer. It is also known as variac or dimmer stat. It is made of a single-winding coil. This single-winding setup makes them cheaper, more efficient, and have better voltage regulation than normal transformers. They are much more useful in cases in which the voltage ratio is less than 2 … Read more