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. The magnetic blowouts in the pictured albright contactor which is designed for dc. Hence, the motor is subjected to the full voltage of the power supply. Ac contactor is a kind of electromagnetic type contactor with main contact normally open, three phase, using air as arcing mechanism electromagnetic type contactor its components include. Magnetic contactor working principle in english how mc. When discrete ferromagnetic objectssuch as gear teeth, turbine. Magnetic contactors are a form of electrical relay found on most electrically powered motors. In semiconductor testing, contactor can also refer to the specialized socket that connects the. Contactor types, structure and working principle the contactor is a voltagecontrolled switching device suitable for systems that frequently turn on and off the acdc circuit. Contactor types, structure and working principle xinli. Contactor overview function contactors are designed to control 1p, 2p, 3p and 4p circuits up to 100 a.
This includes power contacts, auxiliary contacts, and contact springs. The working principle of a dol starter begins with the connection to the 3phase main with the motor. The power source into the coil of winding,it like the solenoid operation. The excited electromagnet produces a magnetic field. 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. The field attracts a second magnet, which may be a. Magnetic contactor is a switchgear device like a relay but it has the higher current capacity and hence has some extra use in power circuits. Contactors are electrically controlled switching devices used.
This process helps in energizing the moving contact. The working principle of electromagnetic relays is not complicated, and it operates mainly according to the principle of electromagnetic induction. Magnetic type overload relays are generally used in areas. A magnetic pickup is essentially a coil wound around a permanently magnetized probe. A magnetic contactor has two incoming circuits which include the main circuit to power the load and an auxiliary circuit to operate the contactor itself. Contactors electromechanical relays electronics textbook. If the seriesconnected heaters get too hot from excessive current, the normallyclosed overload contact will open. Magnetic contactors are a form of electrical relay found on most electrically powered. The excited electromagnet produces a magnetic field, causing. Contactor relays contactor relays contactor relays are often used in control and regulating functions. A contactor can be used to reduce and control these arcs.
The operating principle of the contactor is quite simple. As the name indicates contactor is used to make or break contacts as like an ordinary onoff switch. The circuit of the magnetic contactor is enclosed in an insulating material like nylon 6, thermosetting plastics and bakelite. The current in the magnetic contactor is carried out with the contacts. 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. Sep 16, 2016 home unlabelled magnetic contactor magnetic contactor working principle electrical engineering friday, september 16, 2016 learning engineering september 16, 2016. Thats why the current passes through the input of the contact of the contactor to the output of the contactor. Download magnetic contactor 1 pole relay wiring pdf. The contact between the strip and the contactor causes the contactor to deenergize and restricts the power to the motor, and thus turns it off. I purchased this motor in auction and all the wires are missing and the contactor s are not working. Magnetic contactor working principle in english how mc works.
The coil gets energizes and start producing magnetic field. When current is passed through the contactor, the electromagnet starts to build up, producing a magnetic field. A normally closed nc contact completes the circuit between the fixed contacts and the moving contacts. 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. Shown here is a contactor for a threephase electric motor, installed on a panel as part of an electrical. Dec 09, 2015 magnetic overload relays magnetic type overload relays operate by sensing the strength of the magnetic. Magnetic contactor is different from relay and circuit breaker. Contactor construction, working principle, application. Contactor types, structure and working principle xinli electric. Pdf magnetic contactor 1 pole relay wiring free files. We arrange the threephase winding in such a manner in the slots that they produce one rotating magnetic field when we switch on the threephase ac supply source. Mini contactor overload cgm s 9 a 120 10 cgt 12 m 0. Operating coils apply common acdc power, ac or dc operation, dc holding.
Magnetic overload relays magnetic type overload relays operate by sensing the strength of the magnetic. Its intensity and direction determine the forces of attraction or repulsion existing between the two magnets. Magnetic contactor magnetic contactor working principle. May 06, 2016 the basic operation of contactors is similar to that of relays but contactor contacts can carry much more current than relays. Magnetic contactor is a device or switch which operate magnetically and close or open the electric circuit.
Working of contactors electronic circuits and diagrams. Contactor relays 52 contactors dil, overload relays z 58 contactors dil 514 overload relays z 520 zeb electronic overload relay 523 zev electronic motorprotective system 526 thermistor overload relay. Nov 27, 2019 the stator of three phase induction motor is made up of numbers of slots to construct a 3 phase winding circuit which we connect with 3 phase ac source. Download magnetic contactor 1 pole relay wiring free files. Magnetic contactor working principle in english how mc works with animation earth bondhon a contactor is an electrically controlled switch. It works on the principle of an electromagnetic attraction. When the circuit of the relay senses the fault current, it energises the electromagnetic field which produces the temporary magnetic field.
Due to the magnetic field the contacts are hold together fixed contacts and moving contacts. A magnetic contactor may be present in a magnetic starter. This type of starting is suitable for small motors below 5 hp 3. The contact includes different contacts like power contacts, contact springs, and auxiliary contacts. Working of relayshow relay works,basics,design,construction. Sometimes an economizer circuit is also installed to reduce the power required to keep a contactor closed. If the seriesconnected heaters get too hot from excessive current, the normallyclosed overload contact will open, deenergizing the contactor sending power to the motor.
The current passing through the contactor excites the electromagnet. When discrete ferromagnetic objectssuch as gear teeth, turbine rotor blades, slotted discs, or shafts with keywaysare passed through the probes magnetic field, the flux density is modulated. Functionalities and characteristics of magnetic contactor. The magnetic contactor is usually paired with an overload relay in a magnetic starter to flick the switch when the motor load exceeds its capacity. When the circuit of the relay senses the fault current, it energises the electromagnetic field which produces the temporary. A contactor is a large relay, usually used to switch current to an electric motor or another highpower load. 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. Magnetic contactor working principle in english how mc works with animation earth bondhon a contactor is an electrically. Magnetic contactor wiring diagram pdf teknik listrik. Where relay can be operated by below 1 amp, magnetic contactor may be used in over 1ka power circuits. It belongs to a kind of control device, and it is one of the most widely used lowvoltage electrical appliances in electric drive system, machine tool equipment control. Working principle conventionally the magnetic amplifiers have been equated with saturable core reactors, which work on the principle of superimposition of magnetic fluxes in the. I hope you will find this article informative and helpful. Star delta connection diagram and working principle.
This magnetic field moves the relay armature for opening or closing the connections. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. In the case of three phase ac alternating current operation, the most widely. A guide about magnetic contactor and its working uses. Note that one one of the contactor acts as a switch for the start button. Home unlabelled magnetic contactor magnetic contactor working principle electrical engineering friday, september 16, 2016 learning engineering september 16, 2016. A dual starter connects the motor terminals directly to the power supply. The auxiliary circuit connects to an induction coil, and. General information technical data nema eemac ratings pdf.
It operates electromagnetically that is it can be operated remotely, less amount of current is enough to make a connection and remove the connection. When the power is on,it energized the coil and make plunger move. 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. Between the mains supply terminals and motor terminals the dol starter main terminals are connected and with the two terminals of the threephase power supply as described in figure 1 the control circuit is energized. Ac contactor is a kind of electromagnetic type contactor with main contact normally open, three phase, using air as arcing.
A simple circuit diagram either of the two start buttons will close the contactor, either of the stop buttons will open the contactor. What is is auxiliary contacts and its working in contactor. They are used in large quantities for the indirect control of motors, valves, clutches and heating equipment. Consequently, high starting current flows through the motor. Difference between ac contactors and dc contactors.
An electrical contactor is a switching device, widely used for the switching of motors, capacitors for power factor correction and lights. Other than the low current contacts, they are also setup with normally open contacts. The contactor is a voltagecontrolled switching device suitable for systems that frequently turn on and off the acdc circuit. In addition to the simplicity which they offer in project engineering, panel building, commissioning and maintenance, the high. Oct 16, 2019 the current in the magnetic contactor is carried out with the contacts. This video explains the principle of operation of contactors. When heavy motor currents are interrupted, they produce arcs. The contacts are the currentcarrying part of the contactor. Large electric motors can be protected from overcurrent damage through the use of overload heaters and overload contacts. The greatest difference between magnetic type and thermal type overload re lays is that magnetic types are not sensitive to ambient temperature.
They are detachable from a motor so that an operator may work with that. The auxiliary circuit connects to an induction coil, and when current flows through the circuit, the coil generates a magnetic field. It can delivery a big ampere to the loads and very long lasting and high durability. Auxiliary contact unit with low level contact s2 types of inputs the long life nocontact output type unsy21, sy31 and contact output type unsy22, sy32 are available. Between the mains supply terminals and motor terminals the dol starter main. Ac contactor working principle and structure general idea about ac contactor. Another type of overload motor is the electronic type which continuously watches the motor current, whereas the thermal overload relay shuts off the motor depending on the rise of temperatureheat of. The basics how inductors work working principle duration. Magnetic contactor working principle in english how mc works with animation earth bondhon a contactor is an electrically controlled. The basic operation of contactors is similar to that of relays but contactor contacts can carry much more current than relays. Ac contactor working principle and structure xinli electric.
How the contactor operates operating principle of a contactor. Large electric motors can be protected from overcurrent damage through the use of overload. The control circuit is connected to any two phases and. Thermal overload relay working principle your electrical. Working principle of contactor is well explained in this article. Dc contactors used magnetic blowouts or specially designed arc chutes for arc extinction. Ac contactor is a kind of electromagnetic type contactor with main contact normally open, three phase, using air as arcing mechanism electromagnetic type contactor.
Contactor magnetic contactors x electrical contactors. They act as a gobetween for direct power sources, and highload. Magnetic contactor is common used in automation industry for motor control application. The energized electromagnet then creates a magnetic field. Working of contactor as contactors are used for highcurrent load applications they are designed to control and reduce the arc produced when the heavy motor currents are interrupted. Switching on the power in the lowvoltage control circuit. Hello,i have a 5hp, 380 volt,3 phase motor that bends reinforcing bars. Hi friends, in this article, i am talking about thermal overload relay working principle and its function in a dol starter. Contactor for a threephase electric motor, installed on a panel as part of an electrical control system. Hence, the motor is subjected to the full voltage of the power. Where relay can be operated by below 1 amp, magnetic.
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