A device by which contacts in one circuit are operated by a change in conditions in the same circuit or in one or more associated circuits. At least, that is, in circles that dont have better things to do thandebate such things. Contactors and relays contactor relays moeller wiring manual 0205 53 5 the system and the standard european standard en 50011 terminal markings, reference numbers and reference letters for certain contactor relays has a direct bearing on the use and application of the modular system. Crane control contactors and relays 67 october 2008 low voltage monitoring relays technical data and specifications frame relay download frame relay pdf ebook frame relay frame relay ebook author by paul glennon frame relay ebook free of registr. Acbs are used for low voltage application below 690volts or it industry level it is called as lt application low tension, vcb are used for medium voltage application such as below 33kv and sf6 circuit breakers are used in high voltage application as well as medium voltage application. Best electrical lecture notes pdf download class tutorials. In previous blog posts, we talked about the differences between iec vs. Both these devices are used for similar purposes and hence people are often confused about the difference between a contactor and a relay. Dol means the motor is connected directly on line using one contactor with no starting circuit to lower the high starting current.
The main difference between the contactor and relay is that, contactor is a high power device while relay is a low power device. The terminals of these coils are arranged on the contactor with simple wiring. Contactors generally are spring loaded to prevent contact welding. Thermal overload relay is a protective device, and that is mainly designed to cut the power whenever the motor uses too much current for an extended time period. It is but one component of a starter and is rated by voltage. Difference between ssr and contact relay faq india omron ia. The msn series contactors, starters and relays can be installed on a mounting rail 35mm width. All moeller contactor relays have doublebreak contacts. Unlike lowerpowered relays, contactors generally have special structures for arcsuppression to allow them to interrupt heavy currents, such as motor. Because of this, relays are often used as a middleman between the electronic circuit and the contactor. Difference between a battery and a capacitor a motor starter is a combined device of contactor and over load relay.
Electrical standards for contactors ac1, ac2, ac3, ac4. Difference between contactors and relays electrical classroom. Magnetic suppression and arc dividers are typically utilized when switching multihorsepower motors. When a relay is used to switch a large amount of electrical power through its. Today were going to talk about selecting a contactor for your application requirements. The eutectic overload relay the bimetallic overload relay 15 the solid state overload relay 16. Relay modules switch, isolate, and amplify signals reliably. All dil contactor relays have doublebreak contacts. The main difference between contactors and relays is the loads that they are meant to handle. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This p roduces a retarding effect on motion of the rotor in either di rection. A contactor joins 2 poles together, without a common circuit between them, while a relay has a common contact that connects to a neutral position.
However i would advise periodic inspection to see the condition of the relay or contactor such as condition of the coil if its visible from outside, including any testings if required. What is the difference between a relay and an optocoupler. Contactors and contactor assemblies digital asset management. Examplein terms of usage say a person wants to turn on 500 kw motor, he could simply. Contactor and relay are two terms often encountered when dealing with electric circuits. Electrically, we have transistors and integrated circuits.
This article clarifies the differences between the two devices to remove any confusion once and for all. What is the difference between solidstate relays ssrs and contact relays. Its coil is wired in parallel with the safety circuits, and in series with the contactor coil. A 90340 is a very common, versatile relay that many techs have on their truck so we will use it as the example. It is a special type of relay, but there is a basic difference between the contactor and a relay. In addition to their current ratings and rating for motor circuit control, contactors often have other construction details not found in relays. Difference between contactor and relay compare the. On the other hand, a contactor is designed to provide large number of operations at typical rated loads of 200400600 amps at. Start studying unit 11 contactors, relays, and overloads. Af contactors 3pole contactors and overload relays for. Thermal overload relay is a protective device, and that is mainly designed to cut the power whenever the motor uses too.
What is the difference between relay and contactor answer pankaj relay. Relays are typically integrated into a logic circuit together with other relays. Semantics the differentiation between a relay and a contactor is a subject often debated in some engineering circles. Main difference between contactor and starter electrical. What is the difference between the contactor and circuit breaker. A wiring diagram is a simplified conventional pictorial representation of an electric circuit. Difference between ac1 and ac3 contactors is ac1 contactor are used for less inductive loads such as resistive loads the power factor of the load is near about 1 but ac3 duty contactors are used for high inductive, squirrel cage motors which will be off during the motor is running condition. A motor starter is simply a contactor plus an overload relay and is rated by motor hp or amperage. Contactors are nothing more than a coil and a set of contacts. The operation of a normally closed relay is the same to that of a normally open relay, except backwards. Ssrs solid state relays use semiconductors for nocontact operation.
They both are commonly used in industrial and commercial applications, and. Here are a few of the basic differences that distinguish different types of relay and contactor switches. Overload relays are classified into two types namely thermal overload relay and magnetic overload relay thermal overload relay. Contactors are used in control circuits with both low and high ampere capacity that is between 15a to 12500a. Solidstate relays ssrs control load currents through use of solidstate switches such. The difference between them is in term of their application and.
How to do contactor wiring for 3 phase induction motor with 3 pole circuit breaker overload relay nonc push button switches in this tutorial post i will tell you about motor contactor wiring and its diagram. Relays are classified into several types based on their functionality and application they are implemented for. Therefore, ssrs have a variety of features that contact relays do not incorporate. Relay operation all relays operate using the same basic principle. To turn things on and off, we need devices that are switchable by the application of a current or voltage.
Hvacr electricalcms, 10 of 14, relays, contactor, and starters. Difference between a switch, relay, circuit breaker and contactor. The contactor is the relay to use when a circuit must support a heavy current load. What is the difference between dol and stardelta starter. When the electricity of one store,ie, is turned off we apply a small signal to activate the contactor,a large box. Difference between ssr and contact relay faq india. Top 19 difference between acb, vcb and sf6 video included. The contactor relay contacts themselves constitute a considerable safety feature. However, the basic difference between the relay and contactor is that the contactor is used in applications with higher current carrying capacity, whereas the relay is used for lower current applications. Differences between circuit breaker and contactor a circuit breaker is designed for high throughfault and interrupting capacity and as a result has a low mechanical life. Dec 11, 2017 much like a relay, a contactor is an electrically controlled switch. These classifications include electromagnetic, solid state, high voltage, thermal relays, and so on. Mar 12, 2017 contactor vs relay difference between relay and contactor to turn things on and off, we need devices that are switchable by the application of a current or voltage.
The contactor applies voltage to a contactor coil to close the contacts and to supply and interrupt power to the circuit. Fundamentals of relay technology application note 1 fundamentals of relay technology electromechanical relays are us ed as interface modules between the process io devices, on the one hand, and the openloopclosedloop control and signaling equipment, on the other, for level and power adjustment purposes. A device by which contacts in one circuit are operated by a change in conditions in. With the complete af contactor range, functionality is improved. The contactor is mostly used in applications where higher current carrying capacity is involved, while the relays are used for lower current applications. A circuit breaker is a simple switch,it can make,break and carry current in normal,overload and short circuit condition. Contactors and relays perform the same task of switching a circuit.
B series contactors general information iec contactors nonreversing and reversing iec. Rather, the term, contactor is used to describe a type of device that is used very much in the same manner as a relay. The relay is controlled device which opens and closes contacts in order to effect operation of other devices in the same or another electric circuit. The differentiation between them is that by definition a contactor must carry a motor control rating in hp or kw, whereas a similar solid state relay. So if an output frekwently must go on and of then its better to use transistoroutputs. Dc relays use a freewheel diode that discharges the electromagnetic force that gathers in the inductance when the coil is deenergized, according to. The relay is controlled device which opens and closes contacts in order to effect operation of. In motor starter, contactor controls the flow of electric current to the connected motor and repeatedly make and break interrupt the power circuit from main power supply. Industrial relay system from coupling relay to replacement for small power contactors coupling relay between the controller and the field the rif0 and rif1 relay modules are used in particular to safely couple signals between the controller and the field. If you see from the application point of view, you would have seen contactors placed in control panels of industrial motors or other heavy loads. The relay contacts are designed not to reflect any radio frequency power back toward the source, and to provide very high isolation between receiver and transmitter terminals. Transistor outputs, relay outputs difference entries.
What is the use of the potential free contacts of a relay. This page compares relay vs contactor and mentions difference between relay and contactor what is relay. Dec 14, 2012 relaisoutputs have free kontakts, so you can use them on every voltage between 3 and 250v ac or dc. Auxilary and power contactor,it can make,break and carry only in overload and normal condition. While the ac contactor is considered to be a more reliable and cheaper product, the dc contactor is engineered to allow custom speed and torque.
Contactor vs relay electrical engineering stack exchange. The characteristic impedance of the relay is matched to the transmission line impedance of the system, for example, 50 ohms. Bf series contactors threepole contactors, 110 to 630a iecac3 duty fourpole contactors, 160 to 1600a iecac1 duty 100 to 500hp 600v ulcsa screw termination. The contactor is safely operated in an always optimized condition making it virtually noise free. Difference between contactor and relay difference between. The electronic circuit provides the power to turn the relay on, which in turn switches a larger voltage source needed to turn on a contactor. By design and construction they ensure potential isolation between the actuating circuit and the operating circuit, in the deenergized state, between the contact input and output. The main difference between a circuit breaker and a contactor is that a circuit breaker is designed to detect and switch a shortcircuit current and overload current when applicable,whereas. What is the difference between a contactor and a starter. Solid state relays ssrs and solid state contactors sscs are essentially if not exactly, the same functionally. A reader submitted a question through the ask chris form. In other words, when the relay control coil is not energized, the relay. Ssrs, however, consist of electronic parts with no mechanical contacts. Contactor vs relay difference between relay and contactor.
They both are commonly used in industrial and commercial applications, and function in almost the. The coil of the contactor can be 24, 115, or 230 v, and even higher depending on the application. Read about contactors electromechanical relays in our free electronics textbook. Contactors and relays are two closely related terms leading to confusions and misinterpretations most of the times. Ssrs are not very different in operation from contact relays electromagnetic relays. This is ideal for projects that do not follow an already existing template, such as building a robot arm from scratch. The terms solenoid and relay can often be used interchangeably. By common usage, the term, contactor is applied to a special type of device that is functionally similar to the relay. A starter has overload protection devices, while a contactor doesnt. Ive expanded the original question from what are the differences between relays, contactors and motor starters. Contactors electromechanical relays electronics textbook. Mar 07, 2017 difference between relay and contactor. How to size a contactor for any application springer. Apr 03, 2019 how to do contactor wiring for 3 phase induction motor with 3 pole circuit breaker overload relay nonc push button switches in this tutorial post i will tell you about motor contactor wiring and its diagram.
In general contactors are intended to control higher levels of current. The basic principle of operation of the contactor and the relay are the same. What is not a typical operating voltage used for relays, contactors. Explain the difference between a manual contactor and a magnetic contactor. Selecting a solid state relay or a solid state contactor for. Differences between circuit breaker and contactor a circuit. The arcs produce additional heat, which, if continued, can damage the contact surfaces. Difference between relay and circuit breaker the difference between the relay and circuit breaker is explained on the various factors like the principle of their operation, working of relay and circuit breaker, type of device they are, voltage, their usability and whether it works as an amplifier or not. Different types of overload relays connection diagram. Both of them are electrically operated switches used for control and switching of loads. Furthermore, the distance between the center of the rail and the coil terminals is unified at. They both are commonly used in industrial and commercial applications, and function in almost the exact same way.
Difference between acb vcb and sf6 circuit breaker. Transistoroutputs make no noise, and have no moving parts. Difference between circuit breaker and disconnectorisolator. Understanding relays page 4 autoshop, all rights reserved. What is the difference between a contactor and a relay. A contactor is an electrical device which is used for switching an electrical circuit on or off.
The contactor arrangement can be single pole, double pole, or triple pole, depending on the phase and application. Ip rating for electrical enclosure 11kv415v over head line specification as per rec abstract of national skip to content engineering interview questions,mcqs,objective questions,class notes,seminor topics,lab viva pdf free download. Manual starter operation with optional operator panel. The main difference between contactors and relays is. Still, the total number of product variants compared to a conventional range is reduced by 90%. Its points are a part of the safety circuit so that when the impedance relay is energized by the opening of a safety control it locks out the contactor. Therefore, this document is intended to describe about a few basic types of relays that are popularly used in typical loadcontrol. May 12, 2015 all electrical equipment has a definite life span and its replacement depend upon the manufacturers advice. The most distinct part of optocoupler as a switch is to isolate low voltage circuit from high voltage circuit. Choosing between a relay and a contactor isnt really difficult. Relay vs contactordifference between relay and contactor. Lowconsumption versions for control relays and 938a contactors in ac3 duty. Relays can be used for many different control applications including controlling fans, blowers, other relays or contactors, valves, dampers, pumps and much more. Much like a relay, a contactor is an electrically controlled switch.