In most cases, the contactor does not simply wear out from normal use. Ac electromagnetic contactors lowvoltage switchgear and control gear part 51. Most motor applications require the use of remote control devices to start and stop the motor. Whatever the application, the function of the contactor is always the same. These relays are constructed from electrical, mechanical and magnetic components, and possess operating coil and mechanical contacts. Practically, a relay is an amplifier, since it is able to control a high power output through a low power input. Ac electromagnetic contactors lowvoltage switchgear and control gear. Electromagnetic contactor with case kasuga electric works. A contactor is an electrically controlled switch used for switching a power circuit, similar to a relay except with higher current ratings. The more expensive the electrical gear, the greater the number of relays that will generally be used.
Therefore, this document is intended to describe about a few basic types of relays that are popularly used in typical loadcontrol. Interrupting ac circuit current is not much of an issue because the current goes to zero twice per cyc. When a relay is used to switch a large amount of electrical power through its contacts, it is designated by a special name. These types of electromagnetic relays can be utilized as either magnitude relay or ratio relay. This equipment includes programmable logic controllers plcs timing relays and coupling modules, whose operation can be adversely affected by disturbances from interactions between all the components. There are posts on the working of relays, types of relays and so on. Operating coils apply common acdc power, ac or dc operation, dc holding, absolutely free of electromagnetic noise. Although the electric motor may operate on threephase, 480 volt ac power, the contactor coil and the rest of the control circuitry operates on a lower voltage for reasons of safety.
Control circuit devices and switching elements electromechanical control circuit devices protective relays of thermal type and electromagnetic type for induction motors ac electromagnetic switches none none none necessary u. Unlike generalpurpose relays, contactors are designed to be directly connected to high. Abb electromagnetic contactors all the products on. Type s contactors are available in nema sizes 007 and are designed for operation at 600 volts maximum. Contactors, overloads and manual motor starters carlo gavazzi. Electromagnetic relay working types of electromagnetic. On the relay mounted to electromagnetic contactor at factory, marked i type name is not indicated. It is a type of a magnetic switch which uses the magnet for creating a magnetic field. The drive, which is of bistable type, is fitted with an opening and a closing coil. Basic relays electromagnetic attraction and induction relays.
Types and model arrangements of electromagnetic contactors and switches tr12600a 9 types h l 10600c frame h g 10800c frame xs4 x 38 contacts 5 types contactor relays dc operated electromagnetic contactors latched electromagnetic contactors heavy load electromagnetic contactors thermal overload relays electromagnetic contactors electromagnetic switches without enclosure with enclosure nonreversible type hs 850 frame. Contactors electromechanical relays electronics textbook. As discussed later in this course, some magnetic contactors are used to control the distribution of power in lighting and heating circuits. Contactors and relays contactor relays eaton wiring manual 0611 53 55 the system and the standard european standard en 50011 terminal markings, distinctive numbers and reference letters for certain contactor relays has a direct bearing on the use and application of the modular system. Contactors are popularly used with electric motors. The basics of contactors contactors are useful in commercial and industrial applications, particularly for controlling large lighting loads and motors. Relays and contactors use a variety of technologies to switch signals and power connections. Type esb standard contactor with 4 ratings from 20 a to 63 a. Sizes 002 contactors use a class 9999 sx11 auxiliary contact as the holding circuit contact. The product offering starts with mini contactors in a compact 12 amp frame size, followed by midi contactors in up to 100 amp frame sizes, and topped off with the power contactors which offer up to 800 amp frame sizes.
These classifications include electromagnetic, solid state, high voltage, thermal relays, and so on. Contactors are relays designed for highcurrent applications. The operating torque is produced by electro magnetic. However, like any other device, they are not infallible. The driver circuits are used to adapt the low voltage. In our opinion, the combination of contactors, which is currently used for motor starting, was replaced with the modern and essentially cheaper construction of the new electromagnetic contactor. The relay operates when the operating force is greater than the restraining force. The product offering starts with minicontactors in a compact 12 amp frame size, followed by midicontactors in up to 100 amp frame sizes, and topped off with the powercontactors which offer up to 800 amp frame sizes. The sc series is a range of long servicelife and highperformance contactors.
Relays are classified into several types based on their functionality and application they are implemented for. Pdf electronic control of an electromagnetic contactor. Sc03 to scn3 smallframe contactors provide snapon fitting of numerous optional units, such as auxiliary contact blocks, coil surge suppressors, and operation counters. Contactors contactors electro magnetic contactors electropneumatic. Every time you turn on a light, fire up a computer or grab a drink from the fridge, you should thank an electrician for delivering the power you need. Contactors and contactor relays with ring tongue terminals. This electromagnetic field attracts the metallic rod armature towards the gap in the hollow cylindrical magnet. Although they have been explained in earlier posts, their wide use and significance needs to be explained in detail. Mar 07, 20 contactors are used by electrical equipment that is frequently turned off and on with the opening and closing of a circuit. The magnetic field then uses for opening and closing the switch and for performing the mechanical operation. This paper describes the development, making and laboratory testing of the new electromagnetic contactor. Magnetic motor starters and magnetic contactors note this mark indicates ec directive compliance. There are different types of contactors, and the various types have their own sets of features, applications, and capabilities.
A normally open holding circuit contact for three wire control is provided as standard. Contactors can break current over a wide range of currents, from a few amperes to thousands of amperes, and voltages from 24 vdc to thousands of volts. Fundamental relayoperating principles and characteristics 19 singlequantity relays of the electromagnetic attraction type here we shall consider plungertype and attractedarmaturetype ac or dc relays that are actuated from either a single current or voltage source. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Magnetic contactors, similar to the ones shown below, are commonly used to provide this function. Electromagnetic contactor with case kasuga electric. The magnetic coil is switched directly on and off with the control supply voltage us by. Motor starters, contactors, and relays all operate on the same basic principle. Contactors are useful in commercial and industrial applications, particularly for controlling large lighting loads and motors. In this lesson well introduce the contactor, the principal interaction point between the control and power aspect of an electrically controlled system using motors.
Type e combinations compy with en 50011 and are to be given. Air products and controls multivoltage relay module. This means that generally the operating coils do not have polarity. In contactors with split electromagnets, the movable half of the electromagnet is attracted towards the fixed electromagnet. Electromagnetic contactor is a single pole heavy duty contactor designed to be used on traction vehicles. The power circuit is engaged once the manual controller is activated by an operator.
There are different types of contacts in a contactor namely, contact springs, auxiliary contacts, and power contacts. Several types of contractors qualify as electricians. Polarized relays use the magnetic flux of the permanent magnet in their electromagnetic sections. As the name indicates contactor is used to make or break contacts as like an ordinary onoff switch. There are different types of contactors like, contactor springs, auxiliary contactor power contactor and capacitor duty contactor. Like most threephase contactors, this ones coil is rated for 120 volts ac. The magnetic drive adapts perfectly to this type of apparatus thanks to its precise and linear travel. A wide variety of electromagnetic contactor options are available to you, there are 1,217 suppliers who sells electromagnetic contactor on, mainly located in asia. The armature is hinged to the yoke and mechanically linked to one or more sets of moving contacts.
Attraction armature type relay is the most simple both in construction as well as in its working principle. Contactors are used by electrical equipment that is frequently turned off and on with the opening and closing of a circuit. These types of contactors can be relatively small in size and come in a variety of voltage ratings, up to 600v. As a result, these magnets will stick to your fridge anytime. Each type of contact has an individual role to play. The first three steps for selection will be the same.
Permanent magnets contain a combination of iron, cobalt and nickel metals, which produce a continuous magnetic field. They act as a gobetween for direct power sources, and highload electrical motors in order to homogenize or balance out changes in electrical frequency which may come from a power supply as well. The function of the contactor is to make and break all power supply. Two types of contactors are defined by nema electronic and magnetic.
Contactors are used by electrical equipment that is frequently turned off and on opening and closing the circuit, such as lights, heaters, and motors. Rotating armature generator in the rotating armature ac generator as illust rated in figure 1, the stator provides a stationary electromagnetic field. A wide variety of electromagnetic contactors options are available to you, there are 1,219 suppliers who sells electromagnetic contactors on, mainly located in asia. Maintenance of electromagnetic contactor on electric locomotive. Used across low voltage applications, magnetic contactors utilize a magnetic operating principle to control and handle motor loads, lighting systems and heating systems.
Contactors are most commonly used for controlling electric motors. Both have an external envelope to protect all the internal parts from the external environment. A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24volt coil electromagnet controlling a 230volt motor switch. There are various types of contactors, and each type has its own set of. The top countries of suppliers are germany, china, and japan, from which the percentage of electromagnetic contactors supply is 1%, 99%, and 1% respectively. Magnetic motor starters and magnetic contactors series. Internationalization compliant with iec, ce, ul, tuv worldwide standards. A simple electromagnetic relay consists of a coil of wire wrapped around a soft iron core a solenoid, an iron yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one or more sets of contacts there are two contacts in the relay pictured. The contacts are opened and closed by exciting this electromagnetic coil. Two typical manual contactors still in use today engineers eventually made a breakthrough with the magnetic contactor. Electromagnetic contactors are actuated by electromechanical means. Wide range of operating voltage 100240v, 265450v, 440575v, ease of customer use. Mar, 2015 in this lesson well introduce the contactor, the principal interaction point between the control and power aspect of an electrically controlled system using motors.
While there are many different designs, depending on the manufacturer, contactors can be broken down into two main categories, namely ac and dc. Magnetic contactors are a form of electrical relay found on most electrically powered motors. Products with the ce mark can be used for european destinations. Perhaps the most common industrial use for contactors is the control of electric motors. Electromagnetic relays are those relay which operates on the principle of electromagnetic attraction.
In order to work efficiently both ac and dc circuits, the contactors are equipped with arc blowout circuit. By reducing power consumption, they also allow a saving in costs. Contactors are used in applications ranging from the light switch to the most complex, automated industrial equipment. Sometimes called ice cube relays because they are small and square and with clear plastic like an ice cube. Contactors can take over a vast range of currents, ranging from a few to thousands of amperes, and voltage from 25vdc to thousands of volts. New electro magnetic contactor with wide control voltage range. Contactor construction, working principle, application. The range offers two types of installation contactors for different. The manual contactor was a big improvement over the knife blade switch. Types and model arrangements of electromagnetic contactors and switches tr12600a 9 types h l 10600c frame h g 10800c frame xs4 x 38 contacts 5 types contactor relays dc operated electromagnetic contactors latched electromagnetic contactors heavy load electromagnetic contactors thermal overload relays electromagnetic contactors. Magnetic contactors, magnetic starters fuji electric fa.
The range offers two types of installation contactors for different applications. Nonpolarized relays nonpolarized relays do not use a permanent magnet in their electromagnetic section. Misumi offers free cad download, short lead times, competitive pricing, and no minimum order quantity. One of the disturbance factors occurs when inductive loads, such as coils of electromagnetic switching devices, are switched off. Magnetic contactors are the same as the electrical relays which are used in a number of electric motors. The conventional types of electromagnetic relays electromechanical relay has one or more coils, movable elements, contact system etc and its operation depends on whether the operating torque or force is greater than the restraining torque or force. These relays are employed as auxiliary relay, control relay, over current, under current, over voltage, under voltage and impedance measuring. There are various types of contactors, and each type has its own set of features, capabilities, and applications. Variations of manual contactors are still in use today. Electrical contractors provide services that keep our lives running smoothly. An electrical contactor is a switching device, widely used for the switching of motors, capacitors for power factor correction and lights. A contactor is controlled by a circuit which has a much lower power level than the switched circuit. Contactors are type of device which is used for establishing and interrupting current under some controlled or normal conditions. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals.
The types discussed in the following paragraphs are typical of the more predominant ones in use. Types of electromagnets relays are classified into the following types, depending on whether or not they have a permanent magnet. The basics of contactors commercial electric products. A coil solenoid, when energized, that creates a magnetic field. An electromagnetic coil is provided for opening and closing of contacts. The rotor, acting as the armature, rotates in the field. Contactors typically have multiple contacts, and those contacts are usually but not always normallyopen, so that power to the load is shut off when the coil is deenergized. In particular, large electrical gear as generators, motors and. Searching for 2 definite purpose magnetic contactors. The new contactors are designed for a wide control range and can be used with both ac and dc. Whenever the electromagnetic coil is energized, an electromagnetic field is produced. Auxiliary contact block types lszd can be snapped on contac. Rt series 3pole contactors are of the block type design with a large coil. To complement the contactors, thermal overloads are offered for each frame size, available in several setting ranges.
1187 673 1359 1061 960 1378 1299 864 1516 235 1020 1496 1567 463 113 856 745 643 1311 434 92 250 188 510 494 442 1527 1573 991 209 569 442 1407 1293 503 133 857 488