A saturable reactor in

electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which 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 passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a ...

where the

magnetic core A magnetic core is a piece of 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, generators, ...

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 flow of electric current creates a magnetic field around the conductor. The field strength depends on the magnitude of th ...

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 which 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 whic ...

(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, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxida ...

; the AC current is roughly proportional to the

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

(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.

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 () is a solid-state semiconductor device with four layers of alternating P- and N-type materials used for high-power applications. It acts exclusively as a bistable switch (or a latch), conducting when the gate receives a current ...

dimmer A dimmer is a device connected to a light fixture and used to lower the brightness of the lighting, light. By changing the voltage waveform applied to the lamp, it is possible to lower the luminous intensity, intensity of the light output. Alt ...

s using

triac A TRIAC (triode for alternating current; also bidirectional triode thyristor or bilateral triode thyristor) is a three terminal electronic component that conducts current in either direction when triggered. The term TRIAC is a genericised trad ...

s 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 state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the mo ...

, 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 Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and No ...

.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

References

External links

* Electromagnetic components {{tech-stub

Design considerations

Obsolete technology

See also

Citations

References

External links