A saturable reactor in

electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

is a special form of

inductor An inductor, also called a coil, choke, or reactor, is a Passivity (engineering), passive two-terminal electronic component, electrical component that stores energy in a magnetic field when an electric current flows through it. An inductor typic ...

where the

magnetic core A magnetic core is a piece of magnetism, magnetic material with a high magnetic permeability used to confine and guide magnetic fields in electrical, electromechanical and magnetic devices such as electromagnets, transformers, electric motors, ele ...

can be deliberately saturated by a direct electric current in a control winding. Once saturated, the

inductance Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The electric current produces a magnetic field around the conductor. The magnetic field strength depends on the magnitude of the ...

of the saturable reactor drops dramatically. This decreases inductive reactance and allows increased flow of the

alternating current Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in w ...

(AC).

Design considerations

Saturable reactors provide a very simple means to remotely and proportionally control the AC through a load such as an

incandescent lamp An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a filament until it glows. The filament is enclosed in a glass bulb that is eith ...

; the AC current is roughly proportional to the

direct current Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow throug ...

(DC) through the control winding. The power windings, the control winding, and the core are arranged so that the control winding is well isolated from the AC power. The AC power windings are also usually configured so that they self-cancel any AC voltage that might otherwise be induced in the control winding. Because the required inductance to achieve dimming varies with the size of the load, saturable reactors often have multiple taps, allowing a small inductance to be used with a large load or a larger inductance to be used with a smaller load. In this way, the required magnitude of the control current can be kept roughly constant, no matter what the load is.

Obsolete technology

Saturable reactors designed for mains (power-line) frequency are larger, heavier, and more expensive than electronic power controllers developed after the introduction of semiconductor electronic components, and have largely been replaced by

thyristor A thyristor (, from a combination of Greek language ''θύρα'', meaning "door" or "valve", and ''transistor'' ) is a solid-state semiconductor device which can be thought of as being a highly robust and switchable diode, allowing the passage ...

dimmers using triacs or SCRs. However, as of 2015, there has been renewed interest in using these devices for control of "smart grids" with multiple current tested installations in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, as well as the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

.Young, Marcus Aaron II, "Saturable Reactor for Power Flow Control in Electric Transmission Systems: Modeling and System Impact Study. " PhD diss., University of Tennessee, 2015

Retrieved on Jun 19 2020.

Citations

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External links

* Electromagnetic components {{tech-stub

Design considerations

Obsolete technology

See also

Citations

References

External links