The terminals of these coils are arranged on the contactor with simple wiring. 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. Much like a relay, a contactor is an electrically controlled switch. Difference between contactors and relays electrical classroom. A starter has overload protection devices, while a contactor doesnt. 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. The characteristic impedance of the relay is matched to the transmission line impedance of the system, for example, 50 ohms. Examplein terms of usage say a person wants to turn on 500 kw motor, he could simply. What is the difference between a contactor and a relay. Transistor outputs, relay outputs difference entries. Difference between ssr and contact relay faq india.
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. In addition to their current ratings and rating for motor circuit control, contactors often have other construction details not found in relays. May 12, 2015 all electrical equipment has a definite life span and its replacement depend upon the manufacturers advice. Relay operation all relays operate using the same basic principle. 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. Here are a few of the basic differences that distinguish different types of relay and contactor switches. A motor starter is simply a contactor plus an overload relay and is rated by motor hp or amperage. The difference between them is in term of their application and. Ssrs are not very different in operation from contact relays electromagnetic relays. They both are commonly used in industrial and commercial applications, and function in almost the exact same way. 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. Magnetic suppression and arc dividers are typically utilized when switching multihorsepower motors. 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. The operation of a normally closed relay is the same to that of a normally open relay, except backwards.
Contactors are used in control circuits with both low and high ampere capacity that is between 15a to 12500a. The eutectic overload relay the bimetallic overload relay 15 the solid state overload relay 16. The most distinct part of optocoupler as a switch is to isolate low voltage circuit from high voltage circuit. What is the difference between dol and stardelta starter. Contactor vs relay difference between relay and contactor. Relays are classified into several types based on their functionality and application they are implemented for.
A 90340 is a very common, versatile relay that many techs have on their truck so we will use it as the example. This p roduces a retarding effect on motion of the rotor in either di rection. By design and construction they ensure electrical isolation between the actuating circuit and the operating circuit, in the deenergized state, between the contact input and output. Main difference between contactor and starter electrical. What is the difference between a contactor and a starter. Relays are typically integrated into a logic circuit together with other relays. Differences between circuit breaker and contactor a circuit. Difference between ssr and contact relay faq india omron ia.
A wiring diagram is a simplified conventional pictorial representation of an electric circuit. 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. Relays can be used for many different control applications including controlling fans, blowers, other relays or contactors, valves, dampers, pumps and much more. Contactors electromechanical relays electronics textbook. 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. With the complete af contactor range, functionality is improved.
Best electrical lecture notes pdf download class tutorials. Difference between circuit breaker and disconnectorisolator. 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. Electrically, we have transistors and integrated circuits.
Difference between a battery and a capacitor a motor starter is a combined device of contactor and over load relay. Bf series contactors threepole contactors, 110 to 630a iecac3 duty fourpole contactors, 160 to 1600a iecac1 duty 100 to 500hp 600v ulcsa screw termination. 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. Thermal overload relay is a protective device, and that is mainly designed to cut the power whenever the motor uses too. The basic principle of operation of the contactor and the relay are the same. What is the difference between solidstate relays ssrs and contact relays. Rather, the term, contactor is used to describe a type of device that is used very much in the same manner as a relay. Manual starter operation with optional operator panel. So if an output frekwently must go on and of then its better to use transistoroutputs. The relay is controlled device which opens and closes contacts in order to effect operation of. Dec 14, 2012 relaisoutputs have free kontakts, so you can use them on every voltage between 3 and 250v ac or dc. The contactor arrangement can be single pole, double pole, or triple pole, depending on the phase and application.
Dec 11, 2017 much like a relay, a contactor is an electrically controlled switch. The contactor is the relay to use when a circuit must support a heavy current load. As such, power is amplified, voltages are adjusted or signals are electrically isolated. Ssrs solid state relays use semiconductors for nocontact operation. 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. A reader submitted a question through the ask chris form. All dil contactor relays have doublebreak contacts.
Relay vs contactordifference between relay and contactor. 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. Different types of overload relays connection diagram. How to size a contactor for any application springer. The contactor relay contacts themselves constitute a considerable safety feature.
A device by which contacts in one circuit are operated by a change in conditions in. Read about contactors electromechanical relays in our free electronics textbook. 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. Contactors are typically built for and used in 3phase applications where a relay is more commonly used in single phase applications. The coil of the contactor can be 24, 115, or 230 v, and even higher depending on the application. What is the difference between a relay and an optocoupler. All moeller contactor relays have doublebreak contacts. Overload relays are classified into two types namely thermal overload relay and magnetic overload relay thermal overload relay. To turn things on and off, we need devices that are switchable by the application of a current or voltage. 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. Contactors generally are spring loaded to prevent contact welding. Contactors and relays perform the same task of switching a circuit.
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. In general contactors are intended to control higher levels of current. Furthermore, the distance between the center of the rail and the coil terminals is unified at. A circuit breaker is a simple switch,it can make,break and carry current in normal,overload and short circuit condition. 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.
Contactor vs relay electrical engineering stack exchange. The main difference between contactors and relays is. B series contactors general information iec contactors nonreversing and reversing iec. Start studying unit 11 contactors, relays, and overloads. 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 main difference between contactors and relays is the loads that they are meant to handle. Selecting a solid state relay or a solid state contactor. Difference between contactor and relay difference between. Contactors are nothing more than a coil and a set of contacts. On the other hand, a contactor is designed to provide large number of operations at typical rated loads of 200400600 amps at. What is not a typical operating voltage used for relays, contactors. Selecting a solid state relay or a solid state contactor for. Top 19 difference between acb, vcb and sf6 video included. A contactor is an electrical device which is used for switching an electrical circuit on or off.
Hvacr electricalcms, 10 of 14, relays, contactor, and starters. Transistoroutputs make no noise, and have no moving parts. They both are commonly used in industrial and commercial applications, and. Auxilary and power contactor,it can make,break and carry only in overload and normal condition. Semantics the differentiation between a relay and a contactor is a subject often debated in some engineering circles. Unlike lowerpowered relays, contactors generally have special structures for arcsuppression to allow them to interrupt heavy currents, such as motor.
Difference between contactor and relay compare the. This section explains the differences between a circuit breaker and a contactor, which both make and break a circuit. What is the difference between relay and contactor answer pankaj relay. Difference between a switch, relay, circuit breaker and contactor. Lowconsumption versions for control relays and 938a contactors in ac3 duty. 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. The arcs produce additional heat, which, if continued, can damage the contact surfaces. When the electricity of one store,ie, is turned off we apply a small signal to activate the contactor,a large box. The contactor is safely operated in an always optimized condition making it virtually noise free.
Relay modules switch, isolate, and amplify signals reliably. 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. The msn series contactors, starters and relays can be installed on a mounting rail 35mm width. Dol means the motor is connected directly on line using one contactor with no starting circuit to lower the high starting current. Mar 07, 2017 difference between relay and contactor. At least, that is, in circles that dont have better things to do thandebate such things. The contactor applies voltage to a contactor coil to close the contacts and to supply and interrupt power to the circuit. Solidstate relays ssrs control load currents through use of solidstate switches such. This is ideal for projects that do not follow an already existing template, such as building a robot arm from scratch. Contactors and relays are two closely related terms leading to confusions and misinterpretations most of the times. Therefore, this document is intended to describe about a few basic types of relays that are popularly used in typical loadcontrol.
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. Understanding relays page 4 autoshop, all rights reserved. The main difference between the contactor and relay is that, contactor is a high power device while relay is a low power device. When a relay is used to switch a large amount of electrical power through its. Unit 19 motor controls big book flashcards quizlet.
Choosing between a relay and a contactor isnt really difficult. Explain the difference between a manual contactor and a magnetic contactor. Both of them are electrically operated switches used for control and switching of loads. Therefore, ssrs have a variety of features that contact relays do not incorporate. Difference between acb vcb and sf6 circuit breaker. Its coil is wired in parallel with the safety circuits, and in series with the contactor coil. In previous blog posts, we talked about the differences between iec vs. Contactor and relay are two terms often encountered when dealing with electric circuits. Ssrs, however, consist of electronic parts with no mechanical contacts.
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. 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. Contactors and contactor assemblies digital asset management. What is the use of the potential free contacts of a relay. These classifications include electromagnetic, solid state, high voltage, thermal relays, and so on.
Af contactors 3pole contactors and overload relays for. This page compares relay vs contactor and mentions difference between relay and contactor what is relay. Learn vocabulary, terms, and more with flashcards, games, and other study tools. In other words, when the relay control coil is not energized, the relay. This article clarifies the differences between the two devices to remove any confusion once and for all. 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. Ive expanded the original question from what are the differences between relays, contactors and motor starters. 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. 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. Dc relays use a freewheel diode that discharges the electromagnetic force that gathers in the inductance when the coil is deenergized, according to. Solid state relays ssrs and solid state contactors sscs are essentially if not exactly, the same functionally. It is but one component of a starter and is rated by voltage. Still, the total number of product variants compared to a conventional range is reduced by 90%. Both these devices are used for similar purposes and hence people are often confused about the difference between a contactor and a relay.
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. 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. The contactor is mostly used in applications where higher current carrying capacity is involved, while the relays are used for lower current applications. They both are commonly used in industrial and commercial applications, and function in almost the.