What is a Current Transformer?
The current Transformer is a special type of transformer which is designed for a special purpose. it is a device for the transformation of current from a higher value to a lower value or it transfers currently at a higher value to a proportional lower voltage. Current transformers are used with a measuring instrument like Voltmeter, Ammeter, or Control apparatus where the current to be measured is such a magnitude that it can not be measured by using an ordinary Ammeter. In practical Current transformers are used to measure the current of magnitude higher than 100 amperes.
Construction of Current Transformer
The Core of Current transformers is made up of laminations of silicon steel. if a high degree of accuracy is required then a high permeability nickel steel is used for making the core of Current transformers. Same as that of all other transformers it has also primary and secondary winding but the difference is that number of turns in the primary winding is very less as compared to other transformer but in most of the case Current transformer has a Single Turn to carry the current to be measure.
The primary winding of the Current Transformer is Connected in series with the Conductor, in which a large current is flowing. The secondary winding of the Current transformer has many more turns as compared to the number of primary and the ending terminal of the Secondary is Connected with the measuring instrument. As compared to the other transformers, Primary and Secondary windings are insulated from each other. (CTs)
Working Principle of Current Transformer
The working of the Current Transformer is similar to the working of all other transformers. it also works on the principle of mutual induction. We have seen that the primary winding of the Current transformer Consists of Either a few winding or a single turn. This single turn carries a full load of current and creates a low magnetic flux in magnitude because the number of turns is very less.
When this magnetic flux links with the secondary of the transformer, it generates a low current in the secondary which is easy to measure by using any ordinary ammeter. Once the Secondary Current is measured then it is multiplied by the number of the secondary turns which is equal to the magnitude of the primary current which is to measured.
Application of Current Transformer
Current transformers are used to measure electric power in powerhouses, industries, grid stations, and control rooms in industries for metering & analyzing the flow of current in the circuit and also for protection purposes.