Calculation of the induced voltage Ui induced voltage in a cable system depends on the mutual inductance between the core and sheath, wires and eventually current cable length: LM is mutual inductivity core and shell (H / km). Inductivity interplay between core and shell LM calculated as follows: To install the formation of trefoil
Lecture Engineering electromagnetics: Current and conductors include all of the following content: Current and current density, metallic conductors, conductor properties & boundary conditions, the method of images, semiconductors.
semiconductors.In the first category are substances which provide an easy path for an electric current. All metals are conductors, however some metals do not conduct well. Manganin, for example, is a poor conductor. Copper is a good conductor, therefore it is widely used for cables. A non-metal which conducts well is carbon. Salt water is an example of a liquid conductor.
A material which does not easily release electrons is called an insulator. Rubber, nylon, porcelain and air are all insulator. There are no perfect insulators.
Electricity is an invisible force that is used to transfer
energy into heat, light, intelligence, or motion. Electricity
is explained in terms of electrical charge, potential differ-
ence (or voltage), electrical charge flow (or current), and
resistance to current flow. Figure 1-1 graphically illus-
trates electron flow through a conductor by comparing it
with water flow through a pipe. The normal unit of current
measurement is the ampere, whereas the normal unit of
voltage measurement is the volt. The unit of opposition to
current flow, or resistance, is the ohm...
If each voltage is connected to a circuit with the same power factor and the three currents return along the
same conductor, then the vector sum of the three return currents is zero. Thus instead of three full sized
return cables, only one of smaller size is needed. If none of the load is single phase, then the neutral is not
needed at all. High voltage supplies are nearly always three phase without a neutral conductor. There is a
great economy in distribution costs if the electricity can be supplied in three phases. ...
The discovery of high temperature superconductors (HTS) in 1986 by two IBM
scientists led to an unprecedented explosion of research and development efforts
world-wide because of the significant potential for practical applications offered by
these materials. However, the early euphoria created by the exciting prospects was
dampened by the daunting task of fabricating these materials into useful forms with
acceptable superconducting properties. Progress towards this goal has been hindered
by many intrinsic materials problems, such as weak-links, flux-creep, and poor mechanical
If we connect a battery across a body, there is a movement of free electrons towards the positive end. This movement of electrons is an electric current. All materials can be classified into three groups according to how readily they permit an electric current to flow. These are: conductors, insulators, and semiconductors.
In the first category are substances which provide an easy path for an electric current. All metals are conductors, however some metals do not conduct well. Manganin, for example, is a poor conductor. Copper is a good conductor, therefore it is widely used for cables.
The age of electricity began with the work of Hans
ChristianOersted (1777-1851), whodemonstratedin 1819 that a current-caving conductor could produce a magnetic field. This was the first time that a relationship between electricity and magnetism had been established. Oersted’s work started a chain of experiments across Europe that culminated in the discovery of electromagnetic induction by Michael Faraday (1791-1867) in 1831.
THE AMPLITUDE MODULATED RADIO RECEIVER
The electromagnetic disturbance created by the transmitter is propagated by the transmitter antenna and travels at the speed of light as described in Chapter 2. It is evident that, if the electromagnetic wave encounters a conductor, a current will be induced in the conductor. How much current is induced will depend on the strength of the electromagnetic ﬁeld, the size and shape of the conductor and its orientation to the direction of propagation of the wave....
AC motors convert AC electrical energy to Mechanical energy. AC motors:
the armature of rotor is a magnet (different to DC motors).
the stator is formed by electromagnets (like in DC motors). Effects of AC Supply on Magnetic Poles Consider the rotor to be a permanent magnet.
Current flowing through conductors energize the magnets and develop N and S poles.
The strength of electromagnets depends on current.
First half cycle current flows in one direction.
Second half cycle it flows in opposite direction...
Although magnetism has been known since ancient times, the connection between electricity and magnetism was not discovered until the early 19th century. Electromagnetics is the study of electric and magnetic ﬁeld behavior. These ﬁelds arise from charged particles both at rest and in motion, and they may exert forces on other charged particles and materials. Hans Christian Oersted (a Danish scientist) demonstrated the relation between electricity and magnetism. In 1819, he showed that a compass needle could be deﬂected by a current-carrying conductor.
A lightning protection system is a system designed to protect a structure from damage due
to lightning strikes by intercepting such strikes and safely passing their extremely high voltage
currents to "ground". Most lightning protection systems include a network of lightning rods,
metal conductors, and ground electrodes designed to provide a low resistance path to ground for
ADC is committed to the switchboard cable product line through streamlined engineering and operations;
batch testing at every step in the production process; electrical performance; consistent quality in jacket
concentricity, cable roundness and cable flexibility; and smallest outside diameter of conductor bundles
and cable. To further demonstrate our commitment to this product line, we comply with all known
environmental regulations that affect our cable products and manufacturing processes.