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. Both have an external envelope to protect all the internal parts from the external environment. January 24, 2019. 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). 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. Also, unlike relay contactors cannot provide protection. Relays are switching devices used in any control circuit for checking a condition or multiplying the number of contacts available. A Relay is a switch used as sensing and controlling device which makes and closes the contacts electronically or electromechanically. 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. They are only used in making or breaking the contacts. Relays on the other hand can and often are both Normally Open and/or Normally Closed depending on the desired function. Contactor vs. Relay. These cookies will be stored in your browser only with your consent. This can create the dangerous situation of a circuit being energized when it is supposed to be off. Relays are used for switching of control circuits and cannot be used for power switching with relatively higher ampacity. Another safety feature commonly included in contactors, due to the high loads they typically carry, is arc suppression. Design. Normally, contactors have in- built arc chutes for suppression. The basic principle of operation of the contactor and the relay are the same. Joined Aug 13, 2010 Messages 1,835 Reaction score 86 Location Newton. With a relay there very well could be. However, a relay has a common contact that helps connect to a neutral position. A relay consists of at least two contacts and an excitation coil. Load Capacity. Contactor v/s Relays2. Mekaniko, mayroon kaming mga relay at contactor. 2. Contactor is a high power device. These contacts may be normally open or normally closed. A contactor joins 2 poles together, without a common circuit between them, while a … Linkedin. Spring-loaded contacts help to reduce this chance, as well as ensure all circuits are broken at the same time. A motor starter is simply a contactor PLUS an overload relay and is rated by motor HP or amperage. 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”. In this, we are going to see the 7 … Choosing Between Contactors and … A contactor is really just an overgrown relay. Any one of the the three areas can cause a contactor or relay to malfunction. All rights reserved. Protective relays and circuit breakers must work together to isolate a fault. Active 3 years, 4 months ago. Contactor vs Relay. Since relays aren’t designed for high loads, arcing is less of a concern and arc suppression is much less common on relays. Contactors are chosen upon the ampere ratings of the load. Furthermore, mini-contactor range offers compact dimensions and specific connection possibilities. Contactor en relais zijn twee termen die vaak worden aangetroffen bij het omgaan met elektrische schakelingen. This website uses cookies to improve your experience. (Max 20A), Used in circuits with low and higher ampacity up to 12500A. The Basics. Contactors and relays are two closely related terms leading to confusions and misinterpretations most of the times. • A relay is normally used in appliances below 5KW, while a contactor is preferred when the appliance is heavier. 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. The difference between them is in term of their application and where they are used. The use of a contactor provides a level of isolation away from the high electric currents associated … If this distance is extended further than the energy can overcome, the arc is suppressed. 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. Ask Question Asked 3 years, 4 months ago. 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. Contactor: It is a device which is used for repeatedly establishing and interrupting an electric circuit under normal conditions. 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. Contactors find their applicat… What is the difference between a contactor and a relay? Remember, a contactor and relay is both a switch (contacts) and a load (coil) that controls the switch (contacts). Viewed 10k times 13. Characteristic of Relay & Circuit Breaker. For lower amounts, ordinary relays are used. Our Site uses cookie. By continuing to use our site you are agreeing to our Cookie policy. It is but one component of a starter and is rated by voltage. The overload relay working/function is discussed below.. The main difference between contactors and relays is the loads that they are meant to handle. 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. Relays do not have an arc suppression system built-in. • Since a contactor is required for a higher load, a relay is always cheaper than a contactor. Institute of Electrical and Electronics Engineers. It is mandatory to procure user consent prior to running these cookies on your website. 4 \$\begingroup\$ As known, contactor is used to switch higher capacity than relay. The FLA, RES and LRA are the ratings of the switch / contacts / points portion of the relay / contactor, not the coil portion. Necessary cookies are absolutely essential for the website to function properly. They are provided with two auxiliary contacts – one NO (97-98) and another NC (95-96). In practice, you should be looking at the function as well. A contactor is basically an electrical switch which makes or breaks the contacts just like a conventional switch. They are most commonly used with electric motors and lighting applications. This is to help protect the equipment downstream of the contactor from damage due to current. The coil is just rated for voltage and cycle rate (hz). This is important because in high load situations contacts can weld themselves together. Contents may not be reproduced. Overload Relay Connection Diagram. a power switching solution that can be used to allocate power without manually opening and closing the switch 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. This means that with a contactor, when it is de-energized there is (typically) no connection. You also have the option to opt-out of these cookies. Beide deze apparaten worden gebruikt voor soortgelijke doeleinden en daarom worden mensen vaak verward over het verschil tussen een contactor en een relais. Contactors are switching devices used to control power flow to any load. Share. Mainly used in control and automation circuits, protection circuits and for switching small electronic circuits. The main disadvantage is, the relay needs more wiring for performing different functions. A mercury-wetted relay is a form of relay, usually a reed relay, in which the contacts are wetted with mercury. 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. Contactors require an additional supply (either AC or DC depending upon the type of contactor we use) for excitation. A Contactor is used for switching of motors, capacitors, lights etc, that drains very high current. It differs from the conventional switch due to an electromagnet which it incorporates in order to hold the contacts. It is used for power switching.A relay consists of at least two contacts and an excitation coil. Test button. These contacts may be normally open or normally closed. 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. Page 3 These contacts are closed or opened by exciting the coil. A contactor is a special type of relay used for switching an electrical circuit on or off. Contactors are used for devices that pass more than 15 amps or loads of more than 3kW. Relay on the other hand, is used in control circuits with low Ampere capacity, that is, between 10A and 15A. So What really differentiates the two devices? 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. # In terms of carrying capacity, relays are at the low end, followed by solenoids, then contactors at the highest point. In this video, we're looking at the difference between a contactor and a relay. When selecting between the two, some very general rules you can follow to help. Contactors are typically built for and used in 3-phase applications where a relay is more commonly used in single phase applications. 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. Used in the switching of motors, capacitors, lights etc. However, the solid-state relay has a higher contact resistance and is susceptible to damage from surge currents. The same procedures can be used to check both contactors and relays. Home » About Us » News » Contactors vs Relays: What’s the Difference? The contactor applies voltage to a contactor coil to close the contacts and to supply and interrupt power to the circuit. The AS contactor is efficient and allows you … Overloads are much less common on relays. 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. Much like a relay, a contactor is an electrically controlled switch. The AF contactor technology revolutionizes how we use contactors and allows use in all parts of the world and in all network conditions. contactor vs relay. Contactors vs Relays: What’s the Difference? • In general contactors are little slower than relays • Contactor is so designed that it can be … This category only includes cookies that ensures basic functionalities and security features of the website. The contactor relay contacts themselves constitute a considerable safety feature. It also has limited switching arrangements compared to an electro-mechanical contactor (typically a SPST contact). 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