# Electrical Terms

## Relay

Definition: The relay is the device that open or closes the contacts to cause the operation of the other electric control. It detects the intolerable or undesirable condition with an assigned area and gives the commands to the circuit breaker to disconnect the affected area. Thus protects the system from damage. Working Principle of Relay …

## DC Circuit

Definition: The closed path in which the direct current flows is called the DC circuit. The current flows in only one direction and it is mostly used in low voltage applications. The resistor is the main component of the DC circuit. A simple DC circuit is shown in the figure below which contains a DC …

## Law of Conservation of Energy

Definition: The law of conservation of energy states that the energy can neither be generated nor destroyed. It is converted from one form to another. The total input power is equal to the sum of the following three components; they are the dissipated energy, stored energy and useful output energy.The devices which convert the mechanical …

## AC Motor

Definition: The motor that converts the alternating current into mechanical power by using an electromagnetic induction phenomenon is called an AC motor. This motor is driven by an alternating current. The stator and the rotor are the two most important parts of the AC motors. The stator is the stationary part of the motor, and …

## Lap & Wave Winding

The armature winding is the most important part of the rotating machine. It is the place where energy conversion takes place, i.e., the mechanical energy is converted into electrical energy, and the electrical energy is converted into mechanical energy. The armature winding is mainly classified into types, i.e., the lap winding and the wave winding. …

## Percentage Differential Relay

Definition: The percentage differential relay is defined as the relay that operates on the phase difference of two or more similar electrical quantities. It is the advanced form of differential protection relay. The only difference between them is the restraining coil. The percentage differential relay consists restraining coil for overcoming the trouble arising out of differences in …

## Electromagnetic Relay

Definition: Electromagnetic relays are those relay which operates on the principle of electromagnetic attraction. It is a type of a magnetic switch which uses the magnet for creating a magnetic field. The magnetic field then uses for opening and closing the switch and for performing the mechanical operation. Types of an Electromagnetic Relay By their working …

## Alternating Current (AC)

Definition: The current that changes its magnitude and polarity at regular intervals of time is called an alternating current.The major advantage of using the alternating current instead of direct current is that the alternating current is easily transformed from higher voltage level to lower voltage level. When the resistive load R is connected across the …

## Phase & Phase Difference

Phase Definition: The phase of an alternating quantity is defined as the divisional part of a cycle through which the quantity moves forward from a selected origin. When the two quantities have the same frequency, and their maximum and minimum point achieve at the same point, then the quantities are said to have in the same …