Search results
Results From The WOW.Com Content Network
The term refers to coils wound on plastic, ceramic, or other nonmagnetic forms, as well as those that have only air inside the windings. Air core coils have lower inductance than ferromagnetic core coils, but are often used at high frequencies because they are free from energy losses called core losses that occur in ferromagnetic cores, which ...
The magnetic field of the coil magnetizes the material of the core, aligning its magnetic domains, and the magnetic field of the core adds to that of the coil, increasing the flux through the coil. This is called a ferromagnetic core inductor. A magnetic core can increase the inductance of a coil by thousands of times.
A coil with a core which is a straight bar or other non-loop shape is called an open-core coil. This has lower magnetic field and inductance than a closed core, but is often used to prevent magnetic saturation of the core. A coil without a ferromagnetic core is called an air-core coil. [14] This includes coils wound on plastic or other ...
The henry (symbol: H) is the unit of electrical inductance in the International System of Units (SI). [1] If a current of 1 ampere flowing through a coil produces flux linkage of 1 weber turn, that coil has a self-inductance of 1 henry. The unit is named after Joseph Henry (1797–1878), the American scientist who discovered electromagnetic induction independently of and at about the same ...
It is desirable that the reactor does not go into magnetic saturation during a short circuit, so generally an air-core coil is used. At low and medium voltages, air-insulated coils are practical; for high transmission voltages, the coils may be immersed in transformer oil. Installation of air-core coils requires consideration of the magnetic ...
A choke usually consists of a coil of insulated wire often wound on a magnetic core, although some consist of a doughnut-shaped ferrite bead strung on a wire. The choke's impedance increases with frequency. Its low electrical resistance passes both AC and DC with little power loss, but its reactance limits the amount of AC passed.
For rigid air-core coils, inductance is a function of coil geometry and number of turns, and is independent of current. Similar analysis applies to a solenoid with a magnetic core, but only if the length of the coil is much greater than the product of the relative permeability of the magnetic core and the diameter. That limits the simple ...
This includes coils wound on a plastic or ceramic form in addition to those made of stiff wire that are self-supporting and have air inside them. Air core coils generally have a much lower inductance than similarly sized ferromagnetic core coils, but are used in radio frequency circuits to prevent energy losses called core losses that occur in ...