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(chemical engineering)
A vessel designed to bring two or more substances into contact.
A heavy-duty relay used to control electric power circuits. Also known as electric contactor.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an electrical device used for frequent closing and opening (up to 1,500 operations per hour) of power circuits carrying direct or alternating current. Contactors are widely used for remote control of machinery and apparatus in DC and AC installations at voltages up to 500–650 volts and currents up to 600 amperes.

Contactors are classified as unipolar or multipolar, depending on the number of contact pairs connected to the power circuit. A unipolar contactor has one pair of contacts, one of which is fixed and the other is movable. The movable contact is fastened to the armature of an electromagnet (with a sucking coil mounted on the core). When the control current flows through the coil the armature is attracted by the core and the contacts are closed. Contactors are usually equipped with an arc quencher, which interrupts the electric arc that arises upon separation of contacts (interruption of an electric circuit carrying a current). A contactor is closed by pressing a push button provided in the supply circuit of the sucking coil. A distinction is made between closing contactors, whose contacts are normally open, and opening contactors, whose contacts are normally closed.

The sucking coil in a contactor draws a current that is insignificant in comparison with the current in the circuit being switched. Both the sucking coil and the contact system in a contactor may operate on direct current, or both may operate on alternating current. Contactors that have a contact system for alternating current and a sucking coil for direct current also exist. In a number of designs, the contacts are locked in their closed position by a latch. Locking contacts, which are structurally connected to the latch, automatically disconnect the power to the sucking coil when the main contacts are closed. In this case the closed position of the contactor does not depend on whether the power is connected to the sucking coil. To open the main contacts of this type of contactor, a separate opening coil is required. Contactors are capable of performing several million switching operations. Contactors are manufactured as self-contained, independently mounted devices and as built-in devices in magnetic starters and industrial machines and installations.


Babikov, M. A. Elektricheskie apparaty, part 2. Moscow-Leningrad, 1956.
Chunikhin, A. A. Elektricheskie apparaty. Moscow, 1967.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


Any device for repeatedly opening and closing an electric power circuit.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Multitest announced that its new 0.3-mm-pitch Atlas contactor successfully passed a customer production-floor evaluation.
KILOVAC contactors are highly specialized for use in critical applications with high current systems.
Cohu develops, manufactures, sells and services semiconductor test and inspection handlers, micro-electro mechanical system (MEMS) test modules, test contactors and thermal sub-systems for semiconductor manufacturers and test subcontractors worldwide.
This is done to ensure that that the company can continuously provide customers with the most advanced and innovative semiconductor test contactor solutions in compliance with the highest global quality standards.
The Solicon DRC3 Series are solid state contactors intended for frequently switching on and off three phase loads up to 5 HP, 480 VAC 7.6 Amps.
CECOM LCMC will notify the West Virginia National Guard (WVNG), who is storing replacement contactors. WVNG will ship replacement contactors to customers who have defective ones.
* 3 or 4-phase contactors and overloads for motor, heater, and lighting control.
"In our research, we studied the production of a suitable nano membrane to be used in membrane contactors, and analyzed its application in gas separation processes.
The contactors feature short and stable switching times, high switching frequency, integrated interlock wiring.
The expansion will support the continued growth in its Liqui-Cel Membrane Contactor business and it will enable Membrana to better meet increasing customer demands of membrane and membrane contactors.
The xStart range includes convenient MSC motor starter combinations that need only a single mounting point, PKZ motor protective circuit breakers with enhanced short circuit capacity, compact DIL E mini contactors, long-life DIL M contactors with electronic coil control, and reversing contactor pairs with mechanical interlocks that occupy no additional panel space.