Ideal transformer- The ideal transformer is defined as the imaginary transformer (i.e. not be made in real practice) which has purely inductive windings without any power loss within the particular transformer.
It is said to be a hundred percent efficient because there is no any magnetic leakage flux within the transformer.
There is also the absence of resistance in the transformer. There are no any losses (core loss, copper loss, etc.) and neither stores nor dissipates energy.
Instrument transformers- There are certain types of the transformer that are generally designed for the application in instrumentation which is high accuracy electrical devices. It is the special transformer which is also used in protection relay schemes.
Instrument transformer is used to transform current and voltage levels. There are basically two types of instrument transformer. They are termed as a current transformer and potential transformer. The current transformer together with the voltage transformer is called an instrument transformer.
To step down the amount of current flow in a known ratio, the current transformer is used. It is basically used in the one-degree circuit for the purpose of detecting or sensing the high current flow within the circuit. This type of transformer is also used to measure alternating electric currents. As a result, it converts the high current into the measurable current.
And, the potential transformer is generally used in the circuit where the power rating is extremely small. To step down the amount of voltage in an accurate ratio, the potential transformer is preferred. Basically, this type of voltage transformer is made for low voltage devices.
How Is Eddy Current Related To Hard And Soft Magnetic Material
Eddy Current is related to the Faraday's law of induction. Eddy current flows when the emf (electromotive force) varying with time is induced in the magnetic flux core, producing some amount of heat within the core. It flows in the closed loops within conductors producing the kinetic energy within the magnetic flux core. There is always eddy current loss in the coil which can be minimized by various techniques.In general, there are mainly two types of technology to minimize eddy current loss. It is minimized by achieving high resistivity due to the addition of silicon to steel in the required conductor. Also, each lamination of the metallic parts should be lightly insulated by varnish. By following these two general techniques, the eddy current loss is usually minimized.
Magnetic materials are classified into two major groups. They are termed as hard magnetic material and soft magnetic material. Generally, hard magnetic materials have lower conductivity to minimize eddy current loss as they have high retentivity. Also, the hard magnetic materials are used to manufacture permanent types of magnet. Some of the examples of hard magnetic materials are alloys of aluminum, nickel, and steel.
The eddy current loss is very low in soft magnetic materials as compared to the hard magnetic materials. It is due to the fact that soft magnetic materials have low hysteresis loss. One of the best examples of soft magnetic material is the silicon steel sheet. The soft magnetic material is generally used to manufacture transformer core and armature core. It is mostly used in the field where rapid reversal of magnetization takes place.