The property of a circuit or circuit element that opposes a change in current flow, causing current changes to lag behind voltage changes. It is measured in Henrys.

The phenomenon of a voltage, magnetic field, or electrostatic charge being produced in an object by lines of force from the source of such fields.

Annealing device where the heat is supplied by electrical induction. See Annealing.

Hardening where the heat is supplied by electrical induction. See Hardening.

A furnace where heat is generated in a conducting material by a varying electromagnetic field due to the materials internal losses.

A process of heating by electrical induction. Heat is generated within an electrically conductive body placed in alternative electromagnetic field by means of eddy currents (due to Joule losses) as well as due to hysteresis losses (in the case of heating a magnetic body). With induction heating there is no contact between induction coil and heated body as the electromagnetic field is generated by an induction coil that is placed in close proximity to a heated body. The depth to which the currents penetrate, called penetration depth, is dependent on the frequency of the magnetic field as well as the electrical resistivity and magnetic permeability of the heated material. The frequency of the electrical supply must be chosen to suit not only the application but also the product material and its size and form.

An asynchronous AC machine to change phase or frequency by converting energy from electrical to mechanical, then from mechanical to electrical.

The transformation to martensite through heating and quenching of carbon steel wires creates a very hard and brittle structure of as-quenched martensite that is typically too brittle for commercial use. Reheating of the metal for tempering or stress relieving after hardening decreases or relaxes residual stresses and produces a ductile structure of tempered martensite. Time and temperature are two of the most critical parameters in tempering. Induction tempering differs from conventional way of furnace tempering (i.e., using gas-fired, infra-red or direct resistance furnaces) being a short-time/higher temperature process in comparison to longer-time/lower-temperature conventional tempering.

According to Faraday’s law of electromagnetic induction, a time-varying magnetic field produces a corresponding electric field that is proportional to the time rate of change of the magnetic flux. In other words, alternating voltage applied to induction coil will result in the appearance of an alternating current in the coil circuit, which in turn, will produce in its surrounding area an alternating (changing) magnetic field that will have the same frequency as the coil current. The changing magnetic field induces eddy currents in the metal wire or cable that passes through induction coil. Induced eddy currents have the same frequency as coil current; however, their direction is opposite that of the coil current.

Heating surface layers of the work piece at the depth where required microstructural changes are required using an ability of induction heating (due to selected frequency) to induce power within the certain depth (see skin effect). Thus will provide a martensitic layer on the surface areas of the work piece to increase the hardness, wear resistance and other parameters while allowing the remainder of the part to be unaffected by the process.

Crosstalk resulting from the action of the electromagnetic field of one conductor or the other.

See Reactance.

A device having winding(s) with or without a magnetic core for creating inductance in a circuit.

An electrical signal proportional to the rate of acceleration or deceleration on a roll winding line. It is fed into a current regulator to produce an exact current needed to accelerate or decelerate the roll with constant sheet tension.

The range of electromagnetic wavelengths between the visible part of the spectrum (750 nm) and microwaves (30 µm).

Radiant energy within the wavelength range 780 to 105 nm. It is invisible energy given off by heated bodies, which transmits heat and will pass through glass.

A collection of those telecommunications components, excluding equipment, that together provides the basic support for the distribution of all information within a building or campus.

A casting, suitable for working or re-melting the solidified mass of metal resulting from the pouring of molten metal into a mold. It has a round or rec­tangular cross-section with rounded cor­ners, and the greatest dimension is always the longitudinal. Ingots are always tapered and usually cast big-end-down. In magnesium metallurgy, ingot is a cast slab of solid magnesium for remelting and casting into shapes or for rolling, extrusion or forging.

Steel so low in carbon, silicon, manganese, phosphorus, sulfur and other metalloid content that it is commonly called pure iron. Ingot iron is sometimes used for making enameling sheets. Also, silicon is sometimes added to pure iron to make high-grade electrical sheets.

A mold in which ingots are cast. Molds may be circular, square or rectangular, with walls of various thicknesses. Some molds have a larger cross section at the bottom while others are larger at the top.