May 06, 2016 this video explains the principle of operation of contactors. The spring is used so as to produce an air gap in the circuit when the relay becomes deenergized. Although they have been explained in earlier posts, their wide use and significance needs to be explained in detail. The enclosure is a frame housing the contacts and the electromagnet. The knife blade switch contactors were introduced in the late 1800s. The coil of the contactor can be powered indifferently in ac or dc. Your power is most critical to us and we are available 24x7. These include the power contacts, contact springs, and the auxiliary contacts. It offers the industrial user greater protection and added life for motors in heavy. The magnetic field created is a strong magnetic field that pulls the iron core of the magnetic contractor in the coil and as a result, an electric arc is generated.
Sometimes an economizer circuit is also installed to reduce the power required to keep a contactor closed. Large electric motors can be protected from overcurrent damage through the use of overload heaters and overload contacts. The magnetic field is generated by the electromagnet in the magnetic contractor when the electricity starts flowing in the magnetic contractor. This is one of the most advanced designs of a contactor, which can be operated remotely. Contactor wiring diagram contactor wiring diagram contactor wiring diagram 3 phase contactor wiring diagram ac unit every electrical arrangement consists of various distinct components.
The sc series is a range of long servicelife and highperformance contactors. A pair of fixed contacts is attached to the contactor housing and a pair of moveable ones is attached to the electromagnet, and the force exerted by a spring or gravity keeps them apart. The junction relay for opening and closing the low voltage and minute current is not needed, so this unit is suitable for opening and closing electronic input circuits in. Magnetic contactor working principle in english how mc works with animation earth bondhon a contactor is an electrically controlled switch relay used for switching an electrical power circuit. Class 8502 or 8536, type s, nema size 0, 1, 1p, or 2 the class 9991 oversize enclosures listed in table 6 accept an openstyle contactor or starter, along with a fused controlcircuit transformer form f4t, for field assembly of enclosed controllers. They usually handle very heavy loads like an electric motor, lighting and heating equipments and so on. This is the heart of the contactor, the magnetic coil makes electromagnetic field when rated supply reached on the contacts of the coil denoted as a1 and a2. These parts are safely held with the help of a spring. Contactors can be combined with either manual motor starters of the sm series, providing thermal and magnetic protection up to 100a, or single or threepole thermal bimetallic overload relays, with or without singlephase. When the power is on,it energized the coil and make plunger move. Magnetic contactors, magnetic starters fuji electric fa. How a magnetic contacor works the function of a contactor or motor starter is simple, when the ac supply goes to the contactor coil, the coil make a strong magnetic field and field pulls the iron core to the coil and make a electrical contacts. Thus the moving and fixed contacts make a short circuit.
When current is passed through the contactor, the electromagnet starts to build up, producing a magnetic field. As discussed later in this course, some magnetic contactors are used to control the distribution of power in lighting and heating circuits. A new contactor range from abb new generation abb contactors. A normally closed nc contact completes the circuit between the fixed contacts and the moving contacts. Therefore, the function of the contactor is to switch an electrical circuit on or off. Abb spare parts 11 1 spare parts contactors active products a, af, ae, tae, ua, ua. Select required contactor by catalog number and replace the magnet coil alpha. Mini contactor overload cgm s 9 a 120 10 cgt 12 m 0. Combination of manual motor starters and magnetic contactors a lineup that aims to set a new world standard for compactness. The function of the contactor is to make and break all power supply lines running to a load or to repeatedly establish and interrupt an electrical power circuit. Model comes with saddle clamp terminals, inclined wire guides, captive screws, and is ip20 touchsafe with removable terminal cover. What are nc, no in contactor the nc means the normally close electric circuit or we can said it is a normally close contacts and no meas. Accumulations of dust and dirt on highvoltage equipment can cause. Timer and contactor wiring diagram pdf wiring diagram.
Magnetic starters consist of an electrical contactor and an overload which provides protection in case of a sudden loss of power. Logic functions are common to all areas of industry. What are nc, no in contactor the nc means the normally close electric circuit or we can said it is a normally close contacts and no meas normally open. Electrical symbols and line diagrams university of florida. Soon, manual contactors replaced knife blade switches completely, and even today different variations of these types of contactors are being used.
What is the function of a contactor in an electrical circuit. Model g8293 magnetic switch instruction sheet magnetic switch assembly contactor teco cn16 440v coil thermal overload relay teco rhn10k 2. The electromagnet or coil provides the driving force to close the contacts. If the motor has not been started yet, the magnetic starter does not receive current.
Contactor construction, working principle, application. The sc line up, which is based on high level technology, now extends from the sc03 to the sc. The circuit of the magnetic contactor is enclosed in an insulating material like nylon 6, thermosetting plastics and. A magnetic motor starter is an electromagnetically operated device that starts and stops a connected motor load.
Relays on the other hand can and often are both normally open andor normally closed depending on the desired function. They can also be mounted separately with the panel terminal blocks. It can delivery a big ampere to the loads and very long lasting and high durability. Type s contactors are designed for operation at 600 volts, ac 5060.
Most motor applications require the use of remote control devices to start and stop the motor. Oct 01, 2019 this magnetic field pulls the armature into the coil, and this creates an electrical arc. A contactor is a relay that is used for switching power. The junction relay for opening and closing the low voltage and minute current is not needed, so this unit is suitable for opening and closing electronic input circuits in programmable logic controllers, etc. Ra contactors and contactors relays main contact sets 12 arc chutes lvrt contactor coils 14 spare parts cover 16 spare parts bottom 17 service kit 17 contactor bridge 17 classic products eh, ehdb, ek contactors 3pole contactors type eh 18.
Oct 16, 2019 the magnetic contactor has three main parts components. A magnetic contactor may be present in a magnetic starter as either stationary or moving, together with a solenoid coil, pressure springs, an electromagnet that is kept in place, magnetic shading coils and a mobile armature. Tesys d contactors and reversing contactors are available from 9 a to 150 a inductive motor, and from 20 a to 200 a resistive loads in 3pole and 4pole versions. 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. A contactor is a switching device, having one stable position, operated otherwise than by hand.
A contactor is a large relay, usually used to switch current to an electric motor or another highpower load. The contacts are the currentcarrying part of the contactor. The coil gets energizes and start producing magnetic field. Motor control fundamentals wiki odesie by tech transfer. An example figure 6 would be a magnetic contactor controlled by a toggle switch used to energize and deenergize the contactor, or m coil. A magnetic contactor is operated electromechanically without manual intervention.
This includes power contacts, auxiliary contacts, and contact springs. An electric contactor is a large relay for switching electrical loads on and off in motors and other highpower loads. The excited electromagnet produces a magnetic field, causing the contactor core to move the armature. It is safe to assume that they were probably the first types of contactors that were used. Magnetic contactor is common used in automation industry for motor control application. Designed for a mechanical life of 15 million operations. Magnetic contactors, similar to the ones shown below, are commonly used to provide this function. You can combine a contactor with an overload relay to make a complete motor starter. To complement the contactors, thermal overloads are offered for each frame size, available in several setting ranges. Nema magnetic contactors are commonly used as motor contactors and for switching heating loads, capacitors.
If so the complete contactor needs to be exchanged. The current in the magnetic contactor is carried out with the contacts. Magnetic contactor working principle in english how mc. Abb control secrl 2 20010619 the abb range of a the abb range of a contactorscontactors a 9, a 12, a 16 a 26, a 30, a 40 a 50, a 63, a 75 a 95, a 110 a145, a185 a210, a260, a300 af400, af460 af580, af750. These reliable motor control components are available up to 360 amp capacity and in 1 or 3phase configurations at coil voltages from 24 to 550 vac or 24vdc. As the name indicates contactor is used to make or break contacts as like an ordinary onoff switch.
Magnetic contactors are a form of electrical relay found on most electrically powered motors. Mitsubishis magnetic contactors and magnetic starters. Hum can also occur if the pole surfaces are deformed. This process helps in energizing the moving contact. The magnetic blowouts in the pictured albright contactor which is designed for dc currents more than double the current the contactor can break, increasing it from 600 a to 1,500 a.
Class 8502 contactors are available in nema sizes 007. The contact includes different contacts like power contacts, contact springs, and auxiliary contacts. The relay function can be better understood by explaining the following diagram given below. This means that with a contactor, when it is deenergized there is typically no connection. A guide about magnetic contactor and its working uses.
The power source into the coil of winding,it like the solenoid operation. The diagram shows an inner section diagram of a relay. Contactor link module link module base plate contactor scm series mms contactor sce series mms bm3v series combination starters can be easily configured with a manual motor starter, magnetic contactor and other parts. When the coil is energized, the contacts close, and power flows to the load. Frontmounted operation counter manual operator for easy circuit checking onoff status indicator. Contactors are electrically controlled switching devices used for switching of electrical circuits.
Asked in electrical engineering, industrial electricity and. The af contactor technology revolutionizes how we use contactors and allows use in all parts of the world and in all network conditions. Instead, take a few moments to see if there is an obvious problem. A contactor can be operated by electrical, pneumatic or electropneumatic means. Working of relayshow relay works,basics,design,construction. If the seriesconnected heaters get too hot from excessive current, the normallyclosed overload contact will open. 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. Remove any protective grease or oil which may be on the magnet pole faces, as the grease could collect dust and dirt, thus causing a sticking of the magnet. Abb 3pole contactors offer an exhaustive selection of products for simple and extreme applications as well as products with specific purposes. This magnetic switch toggles a motor on and off, and helps provide thermal overload protection for the motor if operating temperature gradually increases due to heavy work loads. It is an important building block in industrial automation.
A louder hum will occur if the shading coil does not apply to af is broken because the magnet will cause the contactor to chatter. Magnetic starters magnetic contactors thermal overload relays contactor relays optional units product introduction 18 type codes order procedure outline drawing warranty and safety information of our farelated products 32 34 36 44 50 international standard 28 mitsubishis magnetic contactors and magnetic starters continue to push the boundaries. Model c contactor a threephase starter b singlephase starter type. Advanced motor protection and control fuji duo series. The coil energizes the contactor, moving the contacts into position. Sc03 to scn3 smallframe contactors provide snapon fitting of numerous optional units, such as auxiliary contact blocks, coil surge suppressors, and operation counters. Magnetic contactors use a small control current to open and close the circuit. An electrical contactor is a switching device, widely used for the switching of motors, capacitors for power factor correction and lights. Contactors electromechanical relays electronics textbook.
Carefully inspect all parts of the contactor for damage. Auxiliary contact block fits all size contactors03 to n3 snapon mechanical interlock unit can be fixed to equal or unequal size contactors without tools. Thus the current is passed through them to the next circuit. Logic functions control devices such as pushbuttons, limit switches, and pressure switches are connected into a circuit so that the circuit can function in a predetermined manner. There are no live electrical parts for which clearance must be provided between. Electric currents flow in through one contact and into the device in which the contactor is embedded. Optional function unit can be easily added to modify contactor immediately on site. Dec 10, 2017 magnetic contactor working principle in english how mc works with animation earth bondhon a contactor is an electrically controlled switch relay used for switching an electrical power circuit. Model g4674 magnetic switch instruction sheet magnetic switch assembly contactor teco cn16 220v coil thermal overload relay teco rhn10k 12. Iec magnetic contactors provide precise ratings for powercircuit switching and automatic cutoffs during power failures. C contactor a threephase starter b singlephase starter type 25 nonreversing contactors and starters c306 27 nonreversing starters xtob 30 nonreversing starters c440 eol 65 reversing contactors c 2 5 d n a 2 1 5 a a 1 6 1 8 4 contactor frame size a compact, singlepole b compact, twopole c compact, singlepole w. Since a contactor should last for years, dont automatically replace one that fails with an identical unit. Contactors often incorporate magnetic blowout coils, for example, that push the arc away from the contacts as a means of more quickly cooling the arc. Their applications were mostly to control electric motors.
Starters, with overload relays mounted below, can be mounted side by side with a minimum of space between. This means that the contactor can be operated remotely, without the need for putting a person in a potentially dangerous location. Nema contactor and starter specifications technical data. Contactors are almost exclusively designed to operate with normally open form a contacts. Manual guidelines for contactor inspection and maintenance. Functions composite magnetic switch abbreviated as ms is comprised of a contactor for switching on and o. Magnetic contactor the magnetic contactor does not require human intervention and operates electromechanically. Ac magnetic contactors class 8502 general information class 8502 type s magnetic contactors are used to switch heating loads, capacitors, transformers, and electric motors where overload protection is separately provided. To start the motor, the toggle switch is switched on, which energizes the contactor coil and closes the main line contacts, which energizes the motor. Small frame contactors with new functions join the sc series. Enclosures are made of insulating materials such as bakelite. A magnetic contactor may be present in a magnetic starter as either stationary or moving, together with a solenoid coil, pressure springs, an electromagnet that is kept in place, magnetic shading. Contactors up to 150 a for ac3 75 kw 400 v and 200 a for ac1 applications. 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.
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