Insulating Materials for Cables & Electronic Equipments

Insulating Materials for Cables The insulating materials (dielectrics) used for cables must have low discharge current, low dissipation factor (low loss tangent), and should be chemically stable. The materials generally used are impregnated paper, bituminous compounds, rubber, compressed air, mineral oil etc. In the present days, cross-linked polyethylene cables (XLPE)…


Electrical Machine Insulation

In electrical machines, the insulation system must withstand the high electrical stresses and severe mechanical stresses induced by the magnetic field of the moving rotor. In machines, multi-turn windings are put in narrow armature slots, which are usually grounded. Rotating machine stator insulation construction is divided into principal types: Random…


Insulating Materials for Power & Distribution Transformers

The insulating materials used in power and distribution transformers must possess the following properties: Good electrical properties to withstand the power frequency (50 Hz) voltages and impulse overvoltages. Good mechanical properties to withstand fabrication and handling during manufacture and electromagnetic forces during overload, short circuit, and normal operating conditions. Good…


Solid Insulating Materials

Solid insulating materials may be natural organic substances like paper, cloth, rubber, etc. or inorganic materials like Mica, Glass, or synthetic materials like plastics. The different solid insulating materials are: Paper and Pressboards Fibrous materials (unimpregnated and impregnated) Impregnated coating, filling, and bonding materials Resins (Polymers) Natural and synthetic rubbers Inorganic…


Liquid Insulating Materials

An ideal insulating liquid must have following properties: High electric strength, impulse strength, and volume resistivity. Low dielectric dissipation factor. High or low dielectric constant (depending on application). High specific heat and thermal conductivity. Excellent chemical stability and gas-absorbing properties. Low viscosity, low-density, low volatility, low solvent power and high…


Meissner’s Effect and Silsbee Rule

Meissner’s Effect The repulsion of magnetic flux from the interior of a piece of superconducting material as the material undergoes to the transition to the superconducting phase is known as Meissner’s Effect. In superconductor B = 0 µo( H + M ) = 0 M = − H ……………………. (1) Also,…


Types of Superconductor Material

There are two types of superconductor materials Type-1 superconductor Type-2 superconductor Type-1 superconductor They are also called as Soft Superconductor. Their critical field and transition temperature are low. They exhibit complete Meissner’s and Silsbee rule. The change of state from normal to superconductivity and vice-versa is abrupt. Examples: Zn, Pb, Hg, Al, In, etc. Type-2 superconductor…


Semiconductor Materials- Types & Properties

Semiconductor Materials Types Elemental Semiconductor materials Compound Semiconductor materials Amorphous Semiconductor materials 1. Elemental Semiconductor materials Example: Ge, Si, C, B, Al, Ga, P, As, Sb, Bi, etc. a). Arsenic (As) It is pentavalent semiconductor material. It is used as donor N-type semiconductor material. When it is alloyed with gallium, then it is used…


Insulating Materials-Properties & Types

Before selecting an insulation system for a particular application, the following properties need to be considered. Mechanical Thermal Environmental including chemical Electric Economic 1. Mechanical properties The mechanical properties considered are the tensile strength, elongation, tensile modulus, compressive modulus, impact strength etc. 2. Thermal properties Include temperature and time of…


Magnetic Anisotropy

In single crystal material such as iron, the magnetic properties of a material depend on the direction in which they are measured. This property of the magnetic material is called as Magnetic Anisotropy. There are three methods to induce Magnetic Anisotropy Cold Working Magnetic Annealing Magnetic Quenching 1. Cold Working such as cold…


error: Content is protected !!