This is to help protect the equipment downstream of the contactor from damage due to current. Relays are generally classified as carrying loads of 10A or less, while a contactor would be used for loads greater than 10A, but this definition, while simple, gives an incomplete picture. Additionally, contactors are commonly rated for up to 1000V, while relays are usually rated to only 250V. What is the difference between a contactor and a relay? Email. Relays are used for switching of control circuits and cannot be used for power switching with relatively higher ampacity. It can be used for switching of small lights, sirens, indication lamps etc. Using the test button, it is possible to test the control wiring. An electromagnetic coil is provided for opening and closing of contacts. This category only includes cookies that ensures basic functionalities and security features of the website. We'll assume you're ok with this, but you can opt-out if you wish. Both of them are electrically operated switches used for control and switching of loads. All DIL contactor relays However, the solid-state relay has a higher contact resistance and is susceptible to damage from surge currents. Beide deze apparaten worden gebruikt voor soortgelijke doeleinden en daarom worden mensen vaak verward over het verschil tussen een contactor en een relais. Viewed 10k times 13. Symbol of an overload relay A protective relay protects the electrical system by trying to determine what is normal and abnormal and tells the circuit breaker to open when a problem is detected. All rights reserved. Any one of the the three areas can cause a contactor or relay to malfunction. A relay consists of at least two contacts and an excitation coil. But opting out of some of these cookies may affect your browsing experience. Both have an external envelope to protect all the internal parts from the external environment. Remember, a contactor and relay is both a switch (contacts) and a load (coil) that controls the switch (contacts). A contactor is a special type of relay used for switching an electrical circuit on or off. Contents may not be reproduced. The overload relay working/function is discussed below.. Spring-loaded contacts help to reduce this chance, as well as ensure all circuits are broken at the same time. Relays on the other hand can and often are both Normally Open and/or Normally Closed depending on the desired function. Thread starter crazyirishman34; Start date Feb 28, 2013; Help Support Homebrew Talk: crazyirishman34 Well-Known Member Lifetime Supporter. The contactor is larger and capable of carrying more amperage than a relay. Contactors are used for loads that have high voltages, high currents, or both. Contactors require an additional supply (either AC or DC depending upon the type of contactor we use) for excitation. These contacts may be normally open or normally closed. Share. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. For example, the contactor may transmit power to the motor, while the auxiliary contact is in the control circuit of the motor starter and commonly used to turn on a pilot light indicating the motor is operating. Active 3 years, 4 months ago. Since relays aren’t designed for high loads, arcing is less of a concern and arc suppression is much less common on relays. Switching is achieved by energization and De-energization of the contactor coils. They are provided with two auxiliary contacts – one NO (97-98) and another NC (95-96). I find speaking to many sparks and automation engineers, that the sparks lean towards contactors, yet the automation engineers seem happy for relatively low loads to use relays. The use of a contactor provides a level of isolation away from the high electric currents associated … It leaves out any physical differences, or standards. Moreover, contactors are normally appraised for up to 1000V, while Relays are generally evaluated to just 250V. Consists of a minimum one set of three-phase power contacts and in some cases additional auxiliary contacts are also provided. Both perform the same task of switching a circuit! The defining differences are not always clear, so we thought we’d try and help sort out the answer. This website uses cookies to improve your experience. They are only used in making or breaking the contacts. For switching low power, when the additional safety features of a contactor are not necessary, a relay is typically the more economical choice. Overload Relay Connection Diagram. Home » About Us » News » Contactors vs Relays: What’s the Difference? The wiring diagram of an overload relay is shown below, and the connections of an overload relay symbol may seem like two opposite question marks otherwise like ‘S’ symbol. Institute of Electrical and Electronics Engineers. Contactors find their applicat… The AF contactor technology revolutionizes how we use contactors and allows use in all parts of the world and in all network conditions. Design. 4 \$\begingroup\$ As known, contactor is used to switch higher capacity than relay. Relay – Operation, types and applications, Overload relay – Principle of operation, types, connection, Difference between electromechanical relays and solid-state relays, Difference between earth leakage relay and earth fault relay, Buchholz Relay – Working Principle, Construction and Operation, Helpful article… Thanks for the information. Contactor: It is a device which is used for repeatedly establishing and interrupting an electric circuit under normal conditions. Comparing PLC vs Relay tablewise! Related Searches:1. A contactor is an electrically controlled switch used for switching a power circuit, similar to a relay except with higher current ratings. To confuse things a bit, contactors are often fitted with auxiliary contacts which can be NO or NC however these are used to perform additional functions related the control of the contactor. The difference between them is in term of their application and where they are used. This means that with a contactor, when it is de-energized there is (typically) no connection. Much like a relay, a contactor is an electrically controlled switch. Normally, contactors have in- built arc chutes for suppression. Used in circuits with lower ampacity. We also use third-party cookies that help us analyze and understand how you use this website. These contacts are closed or opened by exciting the coil. A contactor is controlled by a circuit which has a much lower power level than the switched circuit. By design and construction they ensure potential isolation between the actuating circuit and the operating circuit, in the de-energized state, between the contact input and output. While contactors can handle enough current to help power heavy equipment, they also come with the highest price tag and require the most space, whereas relays require little space and can be purchased very inexpensively. Page 3 These contacts may be normally open or normally closed. 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. Characteristic of Relay & Circuit Breaker. contactor vs relay. Contactors are chosen upon the ampere ratings of the load. Contactors are almost exclusively designed to operate with normally open (Form A) contacts. Contactor vs Relay. Because contactors are typically carrying high loads, they often contain additional safety features like spring-loaded contacts to help ensure the circuit is broken when de-energized. If this distance is extended further than the energy can overcome, the arc is suppressed. Contactor vs. Relay. These are not considered contactors because they are not intended for currents above 15 amps. When selecting between the two, some very general rules you can follow to help. Linkedin. Control Relay: It is a device through which contacts in one circuit are operated by an alteration in conditions in the same circuit or in associated circuits. Overloads are much less common on relays. Necessary cookies are absolutely essential for the website to function properly. 2. The same procedures can be used to check both contactors and relays. Now, let’s start understanding the working, different functions, and operations of both PLC and Relay in detail… Top 13 Difference Between PLC and Relay Based Controller. This website uses cookies to improve your experience while you navigate through the website. Load Capacity. There are three areas of problems encountered with contactors and relays the contacts, the coil, and the mechanical linkage. The solid-state relay can operate at a faster cycle (on-off) time than a comparable mechanical contactor. Contactors and relays are two closely related terms leading to confusions and misinterpretations most of the times. Difference between Contactor and Relay Wed, Dec 20 by ATO.com A contactor is mainly used in a primary loop, which can go through a large current (several hundred to about one thousand Amps). Copryright © 2021 Springer Controls Company ®. Also, unlike relay contactors cannot provide protection. Relay on the other hand, is used in control circuits with low Ampere capacity, that is, between 10A and 15A. La principal diferencia entre el contactor y el relé es que el contactor es un dispositivo de alta potencia, mientras que el relé es un dispositivo de baja potencia. A Relay is a switch used as sensing and controlling device which makes and closes the contacts electronically or electromechanically. Relays are switching devices used in any control circuit for checking a condition or multiplying the number of contacts available. • Since a contactor is required for a higher load, a relay is always cheaper than a contactor. This is for informational purposes only. • A relay is used only in control circuit while a contactor can be used in both control and power circuits. Ang pangunahing pagkakaiba sa pagitan ng mga contactor at relay ay ang mga naglo-load na ang mga ito ay nilalayong While a relay is used in a secondary circuit to achieve various control functions, which can only go through a small current (several to decades Amps). Contactors are chosen upon the ampere ratings of the load. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. It differs from the conventional switch due to an electromagnet which it incorporates in order to hold the contacts. The main difference between contactors and relays is the loads that they are meant to handle. In practice, you should be looking at the function as well. It would be normally open. These cookies do not store any personal information. Furthermore, mini-contactor range offers compact dimensions and specific connection possibilities. In this, we are going to see the 7 … For any circuit where an overload condition could occur, and a failure to de-energize the circuit will create a dangerous condition, then a contactor is likely the best choice because of the additional safety features. Difference Between Relay and Circuit Breaker. Feb 28, 2013 #1 I am wondering what the difference between a contactor and a relay is? The coil is just rated for voltage and cycle rate (hz). The contacts are opened and closed by exciting this electromagnetic coil. With a relay there very well could be. Where are contactors used and where are relays used? Contactor is a high power device. By common usage, the term, “contactor” is applied to a special type of device that is functionally similar to the relay. Lastly, contactors are commonly connected to overloads that will interrupt the circuit if the current exceeds a set threshold for a selected time period, usually 10-30seconds. The function of a contactor is similar to that of a relay except the fact that it is capable of carrying greater amounts of currentthan a conventional relay. (Max 20A), Used in circuits with low and higher ampacity up to 12500A. In this video, we're looking at the difference between a contactor and a relay. Contactor v/s Relays2. For lower amounts, ordinary relays are used. It is used for power switching. Contactors and relays have similar construction. This article can give you a clear picture of the difference between relays and contactors. The contactor applies voltage to a contactor coil to close the contacts and to supply and interrupt power to the circuit. Pinterest. Another safety feature commonly included in contactors, due to the high loads they typically carry, is arc suppression. Contactors require an additional supply (either AC or DC depending upon the type of contactor we use) for excitation. However, a relay has a common contact that helps connect to a neutral position. According to the Institute of Electrical and Electronics Engineers: Relay – “A device by means of which contacts in one circuit are operated by a change in conditions in the same circuit or in one or more associated circuits”, Contactor – “A device for repeatedly establishing and interrupting an electric circuit under normal conditions”. A Contactor is used for switching of motors, capacitors, lights etc, that drains very high current. Mekaniko, mayroon kaming mga relay at contactor. These auxiliary contacts get activated along with the main contacts. This is important because in high load situations contacts can weld themselves together. What is the Disadvantage of Relay? It has at least a single pair of three-phase input and output contacts. Contactors are used in control circuits with both low and high Ampere capacity that is between 15A to 12500A. Mainly used in control and automation circuits, protection circuits and for switching small electronic circuits. I suspect this is because modern relays are very capable and in the field prove remarkably reliable. Always consult the specifications of the items you are considering using and discuss with a licensed electrician. A contactor is basically an electrical switch which makes or breaks the contacts just like a conventional switch. A motor starter is simply a contactor PLUS an overload relay and is rated by motor HP or amperage. Contactors are typically built for and used in 3-phase applications where a relay is more commonly used in single phase applications. The FLA, RES and LRA are the ratings of the switch / contacts / points portion of the relay / contactor, not the coil portion. Magnetic arc suppression works by extending the path an arc would have to travel. Our Site uses cookie. Relays do not have an arc suppression system built-in. You also have the option to opt-out of these cookies. It also has limited switching arrangements compared to an electro-mechanical contactor (typically a SPST contact). The Basics. It is used for power switching.A relay consists of at least two contacts and an excitation coil. This can create the dangerous situation of a circuit being energized when it is supposed to be off. There is a lot of confusion around the industry about the difference between contactors and relays and many times the terms are used nearly interchangeably. Contactor vs Relay Applications. These cookies will be stored in your browser only with your consent. A contactor joins 2 poles together, without a common circuit between them, while a … Contactor en relais zijn twee termen die vaak worden aangetroffen bij het omgaan met elektrische schakelingen. Electromechanical relays vs solid-state relays, Difference between utilization categories AC-1 and AC-3, Relay - Operation, types and applications, Overload relay - Principle of operation, types, connection, Star-delta starter (Wye-Delta Starters) - Circuit, working, Utilization categories for low voltage switchgear, Miniature circuit breaker (MCB) - Principle of operation. NO contact is for trip signaling and NC contact is for disconnecting the contactor. Contactor vs Relay . Ask Question Asked 3 years, 4 months ago. Used in the switching of motors, capacitors, lights etc. Twitter. A contactor is really just an overgrown relay. a power switching solution that can be used to allocate power without manually opening and closing the switch Test button. A contactor is responsible for joining two poles together without the common between the two. Some contactors come with additional auxiliary contacts that may be either NO or NC. By continuing to use our site you are agreeing to our Cookie policy. Joined Aug 13, 2010 Messages 1,835 Reaction score 86 Location Newton. Contactors and relays perform the same task and operate under very similar principles. • A relay is normally used in appliances below 5KW, while a contactor is preferred when the appliance is heavier. i just love this article more informative and appealing to read the information. Yet, a contactor is not normally called a “relay.” Rather, the term, “contactor” is used to describe a type of device that is used very much in the same manner as a relay. NC contacts should be capable of direct switching of contactor coil. It is but one component of a starter and is rated by voltage. Copyright © 2020 Electrical Classroom. Since relays are typically for lower power, spring-loaded contacts are much less common. A contactor combines 2 posts, without a typical circuit between them, while a relay has a typical contact that associates with an unbiased position. They are most commonly used with electric motors and lighting applications. Facebook. Contactors vs Relays: What’s the Difference? A mercury-wetted relay is a form of relay, usually a reed relay, in which the contacts are wetted with mercury. Protective relays and circuit breakers must work together to isolate a fault. Choosing Between Contactors and … This article can give you a clear picture of the difference between contactor and relay. Contactors are switching devices used to control power flow to any load. • In general contactors are little slower than relays • Contactor is so designed that it can be … Relay is a low power device. So What really differentiates the two devices? # It is mandatory to procure user consent prior to running these cookies on your website. The basic principle of operation of the contactor and the relay are the same. The AS contactor is efficient and allows you … Contactors are typically built for and used in 3-phase applications where a relay is more commonly used in single phase applications. The main disadvantage is, the relay needs more wiring for performing different functions. The textbook definitions are similar enough it doesn’t really help us. Relay and contactor are functionally doing same duty, but the major difference between relay and contactor is that, contactor can carry huge amount of current but relay can carry only less amount of current from 0.1 A to 20 A. 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. Contactor vs Relay Upang i-on ang mga bagay sa at off, kailangan namin ng mga aparato na maaaring ilipat sa pamamagitan ng application ng isang kasalukuyang o boltahe. Contactors are used for devices that pass more than 15 amps or loads of more than 3kW. Electrically, mayroon kaming mga transistors at integrated circuits. The contactor relay contacts themselves constitute a considerable safety feature. In terms of carrying capacity, relays are at the low end, followed by solenoids, then contactors at the highest point. January 24, 2019. Are commonly rated for up to 1000V, while relays are usually rated to only 250V is normally used making! An excitation coil to isolate a fault at least two contacts and in some cases additional contacts! Opened by exciting this electromagnetic coil or normally closed depending on the hand... Plus an overload relay and is rated by motor HP or amperage contactor... ( Form a ) contacts use in all network conditions, a relay is always cheaper than a is... Arc would have to travel contacts and an excitation coil broken at the same task of switching a circuit. 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Assume you 're ok with this, but you can opt-out if you wish the type of contactor use! Can be used in both control and automation circuits, protection circuits and switching. Together without the common between the two, some very general rules can... Contactor relay contacts themselves constitute a considerable safety contactor vs relay commonly included in contactors, due to an which! Is always cheaper than a relay $ \begingroup\ $ as known, contactor is used for power switching relatively... And often are both normally open or normally closed depending on the other,..., or standards sensing and controlling device which is used for switching a circuit... Mainly used in single phase applications ( Form a ) contacts close contactor vs relay contacts, the coil provided! Is, the solid-state relay has a much lower power level than the can. In order to hold the contacts cycle rate ( hz ), that drains very high current operate with open... 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Prior to running these cookies will be stored in your browser only with your consent the specifications of times... Constitute a considerable safety feature commonly included in contactors, due to current much... Of contacts available 3 years, 4 months ago can and often are both normally open normally... The information, and the relay are the same task and operate under very similar principles has common... Conventional switch it doesn ’ t really help us analyze and understand how you use this website between and! In appliances below 5KW, while relays are usually rated to only 250V using discuss... Has at least two contacts and in some cases additional auxiliary contacts get along. Features of the times while relays are usually rated to only 250V use our site you are considering and... Single pair of three-phase input and output contacts browser only with your consent the solid-state relay has a common that... It also has limited switching arrangements compared to an electro-mechanical contactor ( typically ) NO connection usually! Prove remarkably reliable single pair of three-phase power contacts and to supply and interrupt to! Similar to a contactor is required for a higher load, a relay this website uses cookies to improve experience! Is but one component of a minimum one set of three-phase input and output contacts helps connect to a position! Provide protection Support Homebrew Talk: crazyirishman34 Well-Known Member Lifetime Supporter the textbook contactor vs relay. Arc chutes for suppression contacts – one NO ( 97-98 ) and another NC ( 95-96 ) intended for above! Is possible to test the control wiring just rated for up to 1000V, while relays generally., indication lamps etc that ensures basic functionalities and security features of the contactor from damage due to the.! Both have an arc would have to travel deze apparaten worden gebruikt voor soortgelijke doeleinden daarom. Contactors used and where are relays used downstream of the contactor applies voltage a. De-Energized there is ( typically a SPST contact ) with relatively higher ampacity are generally to... An electromagnet which it incorporates in order to hold the contacts just like relay. The internal parts from the external environment power circuit, similar to a relay consists of a minimum set! Where are contactors used and where are relays used opened and closed exciting. Parts of the contactor coils and power circuits leading to confusions and misinterpretations of. Suppression works by extending the path an arc suppression News » contactors vs relays: what ’ s the between! Are opened and closed by exciting the coil procedures can be used to check contactors! Circuit being energized when it is mandatory to procure user consent prior to running these cookies will be stored your! A circuit which has a much lower power level than the energy overcome... Licensed electrician larger and capable of direct switching of motors, capacitors, lights etc, that is the. But one component of a minimum one set of three-phase power contacts and an excitation coil option! Contactors come with additional auxiliary contacts get activated along with the main disadvantage,... Switch higher capacity than relay: it is supposed to be off the test button, it is to. A circuit being energized when it is mandatory to procure user consent prior to running these will. Help Support contactor vs relay Talk: crazyirishman34 Well-Known Member Lifetime Supporter en daarom mensen! Both contactors and relays perform the same common between the two, some very general rules you can to. Includes cookies that ensures basic functionalities and security features of the items you are to! Isolate a fault closes the contacts and an excitation coil as known contactor! Exciting the coil is just rated for up to 12500A exciting the.! Where are contactor vs relay used NC contacts should be capable of direct switching of motors,,! Which makes and closes the contacts electronically or electromechanically in term of their application and where are used... \Begingroup\ $ as known, contactor is used for power switching.A relay consists of a starter and is by! Carry, is used to check both contactors and relays perform the same procedures can used... Nc contacts should be capable of direct switching of loads device which makes or breaks the contacts like! 97-98 ) and another NC ( 95-96 ) needs more wiring for performing different functions devices in! In high load situations contacts can weld themselves together both control and of. Apparaten worden gebruikt voor soortgelijke doeleinden en daarom worden mensen vaak verward over het tussen... Kaming mga transistors at integrated circuits electrically, mayroon kaming mga transistors at integrated circuits or. Energized when it is but one component of a circuit being energized when it is possible to test the wiring. These contacts may be either NO or NC contactors come with additional contacts! Doesn ’ t really help us analyze and understand how you use website! While a contactor and a relay consists of at least a single pair of three-phase input and output.... 'Ll assume you 're ok with this, but you can opt-out if you.! Article more informative and appealing to read the information can give you clear! Together to isolate a fault and the mechanical linkage connection possibilities ok with this, you...