In this article we will discuss about:- 1. Meaning of Fuse 2. Metals and Alloys Used for Fuse 3. Types 4. Merits 5. Demerits. Meaning of Fuse: An electric circuit is designed to carry a definite amount of current. If a much greater current passes through the circuit, there may be serious damages. To check it, a length of a [...]
The various electrical conducting materials are discussed as follows: 1. Copper 2. Aluminium 3. Tungsten 4. Iron and Steel 5. Nickel 6. Tin 7. Lead 8. Alloys 9. Carbon and Graphite 10. Molybdenum 11. Platinum 12. Mercury 13. Non-Linear Conductors. 1. Copper: Properties: (i) Its colour is reddish. (ii) It is highly malleable and ductile. (iii) It can be cast, [...]
In this article we will discuss about:- 1. Introduction to Insulating Materials 2. Characteristics of a Good Insulating Material 3. Classification of Insulating Materials 4. Air Spaces in Insulation 5. Effect of Moisture on Insulation 6. Protection of Insulation against Moisture. Contents: Introduction to Insulating Materials Characteristics of a Good Insulating Material Classification of Insulating Materials Air Spaces in Insulation [...]
The various high resistivity materials (including alloys) are described below: 1. Tungsten: (i) Hard metal. (ii) Resistivity twice that of aluminium. (iii) Can be drawn into very thin wires (for making filaments). The thinner the tungsten wire, the greater is its tensile strength. (iv) In the atmosphere or inert gas (Nitrogen, Argon etc.) or in vacuum, tungsten can be readily [...]
Here is a list of popular electrical materials. 1. Materials of Low Resistivity and High Conductivity: These materials should have the least possible electrical conductivity. They are employed for making conductors for all kinds of windings required in electrical machines, apparatus and devices, as well as for transmission and distribution of electrical energy. Requirements of Materials of High Conductivity: The [...]
Semiconductors are solid materials, either non-metallic elements or compounds, which allow electrons to pass through them so that they conduct electricity in much the same way as a metal. Characteristics of Semiconductors: Semiconductors possess the following characteristics: 1. The resistivity is usually high. 2. The temperature co-efficient of resistance is always negative. 3. The contact between semiconductor and a metal [...]
The properties of insulating materials are enumerated and discussed as under: 1. Electrical Properties 2. Thermal Properties 3. Chemical Properties 4. Mechanical Properties. 1. Electrical Properties of Insulating Materials: i. Insulation Resistance: It may be defined as the resistance between two conductors (or systems of conductors) usually separated by insulating materials. It is the total resistance in respect of two [...]
In this article we will discuss about:- 1. Introduction to Ferroelectric Materials 2. Common Ferroelectric Materials 3. Properties of Ferroelectric Materials in Static Fields 4. Spontaneous Polarisation 5. Applications of Ferroelectric Materials 6. Anti-Ferroelectric Materials 7. Permanent Electric Materials. Introduction to Ferroelectric Materials: If the centre of gravity of the positive and negative charges in a body do not coincide [...]
In this article we will discuss about distance relays and its classification. Introduction to Distance Relays: Distance protection is the name given to the protection, whose action depends upon the distance of the feeding point to the fault. The time of operation of such a protection is a function of the ratio of voltage and current i.e., impedance. This impedance [...]
In this article we will discuss about induction type directional relays used in an electric circuit. Induction Type Directional Power Relay: The non-directional relay can operate for fault flow in either direction. In order to achieve operation for the fault flowing in a specific direction, it is necessary to add a directional element to the non-directional element. The directional (or [...]