Low resistivity materials, Physics

Low resistivity materials: The conducting materials having resistivity between 10-8 to 10-6 ohm-m come under this category and are used in house wiring, as conductors for power transmission and distribution, in the winding of transformer and machines like motors and generators. In fact low resistivity materials are used in all such applications where power loss and voltage drop should be low. Copper and aluminium are examples of commercially acceptable low resistivity than copper but because of its prohibitive cost it uses commercially as a conductor is not feasible. A low resistivity material should have the following additional applications properties:

1.      Low temperature coefficient: This means that the change of resistance with change in temperature should be low. This is necessary to avoid variation in voltage drop and power loss with change in temperature. For example, the resistance of transmission lines which are very long with increase with when exposed with to hot summer sun. This will increase in voltage drop and power loss in the transmission line. The windings of electrical machines and apparatus become hot when the winding has high loaded. This cause temperature rise and if the conducting material of the winding has high-temperature coefficient of resistance, the voltage drop and power loss in the winding will be high.

2.      Sufficient mechanical strength: These materials must withstand with the mechanical stresses developed during its use for particular applications. For examples, the overhead line conductors used for transmission and distribution of electrical power and are subjected to stresses due to wind and their own weight. The conducting materials used for the windings of transformers, motors and generators develop mechanical forces when loaded. These forces can become very large if a high current flows due to a short circuit. Therefore, to withstand the mechanical stresses, developed in the above mentioned application, the conducting material should possess sufficient mechanical strength.

3.      Ductility: Ductility is that property of a material which allows it to be drawn out into a wire. Conductors are required into different sizes and shapes. In some applications round wire section is used, while in other rectangular wire section is used. The conducting material should be ductile enough to enable itself being drawn into different sizes and shapes.

4.      Solderability: The conducting materials are often required to be jointed and the joint must have a minimum contact resistance, which is minimum, if a solder joint is used. Thus, these materials must have good solder ability.

5.       Resistance to corrosion: The material should have a high resistance to corrosion so that it should not be corroded when used in actual or practical environment conditions.

Posted Date: 7/21/2012 7:42:51 AM | Location : United States







Related Discussions:- Low resistivity materials, Assignment Help, Ask Question on Low resistivity materials, Get Answer, Expert's Help, Low resistivity materials Discussions

Write discussion on Low resistivity materials
Your posts are moderated
Related Questions
Q. Under fixed exchange rate, show using a figure, the effects of an expansionary fiscal policy. Show the equilibrium under a flexible exchange rate. Discuss the difference in t

In the Compton effect, a photon of wavelength l collides with a stationary electron.  The wavelength of the emitted photon is: a)  longer than l b)  shorter than l c)

Each particle produces a gravitational field around it which exerts the gravitational force on each of the other particles present within this region. The portion around a point ma

Electric and Magnetic Fields of an Oscillating Charge A 3 dimensional animation of the "far" fields of an oscillating charge. Electromagnetic radiation (EM radiation or EMR) is

Capacitor-start-capacitor-run single-phase motor : In this case, two capacitors are used one for preliminary and other for running purpose as shown. The capacitor used for prelimin

how Michelson interferometer can be used to measure the wavelength of sodium light.

One of the most important theorems in the quantum physics in the Pauli Exclusion Principle, which is based on the experiment observations. The principle explains that “No two elect

Dot Product A Easy demonstration of the relation among the dot product of 2 vectors and the angle among them. Move the slider to view the changes.


Reducing friction with ball bearings  Find two tin cans that have a deep groove approximately the top, such as paint cans. Lay marbles in single groove and invert the other can