Relays, switches, and electrical contacts in general motley. Relay operation all relays operate using the same basic principle. Contactor vs relay difference between relay and contactor. Understanding relays page 4 autoshop, all rights reserved. Contactors are electromechanical switches that allow you to start and stop the flow of current in one circuit. Electrical contactors and relays hvac parts online. The most important difference between an ac and dc contactor is that a dc contactor is designed to suppress electric arcing when the contacts open and close in a dc circuit. Efficiently combine, install and connect motor starters eaton.
What is the difference between solidstate relays ssrs and contact relays. For example, voltages are much lower for dc than ac circuits, and the gaps between contacts are wider in a dc contactor. Mar 25, 2015 this feature is not available right now. The more expensive the electrical gear, the greater the number of relays that will generally be used. 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. Dec 09, 2015 contactors contactors are very similar to relays in that they are electromechanical devices. Difference between contactor and relay difference between. In particular, large electrical gear as generators, motors and. The main difference between contactors and relays are the loads that they are intended to handle.
Difference between ssr and contact relay faq india omron ia. Contactors and relays contactors dil, overload relays z eaton wiring manual 0611 510 5 5 rated operating current ie a ac3 at 400 v max. The main difference between the contactor and relay is that, contactor is a high power device while relay is a low power device. If listing these three e lectromechanical switches in order of carrying capacity, relays would fall at the low end, followed by solenoids, then contactors at the highest point. Hence contactors are used in the switching of heavy loads and power circuits whereas relays are used in the switching of.
Continuous current ratings for common contactors range from 10 amps to. Iec contactors relays a2 springer controls company 96074 chester road, yulee, fl 32097 904 2250575 fax. Breakdown voltages coil rating coil voltage rating all terminals 60 hz rms contact material electrical life mechanical life nominal open max. Contactors and a range of timer and special relays.
Ge controls and power electronics for industrial applications. Ssrs are not very different in operation from contact relays electromagnetic relays. The contactor is the relay to use when a circuit must support a heavy current load. Common applications include industrial electric motors used in heavy trucks and equipment, buses, emergency vehicles, electrichybrid vehicles, boats, light rail, mining, and other systems that simply require too much power for a standard relay. They both are commonly used in industrial and commercial applications, and.
Air products and controls multivoltage relay module. This article clarifies the differences between the two devices to remove any confusion once and for all. A key feature is that the control circuit powering a contactor is electrically isolated from the circuits being switched. Contactors and relays page 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 for machine protection emt6 533 cmd contactor monitoring device 536. When the voltage drops below the point where relays or contactors can. Perhaps the most common industrial use for contactors is the control of electric motors. The distinction between a relay and a contactor is a bit vague, in the sense that. Shop our parts hvac online store for transformers, contactors, and relays hvac supplies and accessories. This is the 10th, in a series of sets, totaling 14 sets in all, that will prepare the student to pass the cms. We offer the best quality hvac contactors and relays you can find. Another difference between contactors and relays is the amount of power that they consume.
They both are commonly used in industrial and commercial applications, and function in almost the exact same way. Relays, contactors, solenoids and pdus for high performance applications relays, contactors, solenoids and pdus for high performance applications te connectivity a new powerful source hv relays dc relays and contactors spacequalified relays and contactors 28 vdc contactors 270 vdc contactors ac contactors kilovac high voltage relays. Unlike relays, contactors are designed to make and break higher powered circuits without being damaged. Directly mountable overload relays provided separately. Also find hard to find transformers, contactors, and relay replacement parts. It consists of a set of input terminals for a single or. The motor statrter is made up of a contactor with an overload relay attached physically and electrically to it. As fully authorized, franchised distributor of relays and contactors, we have contracts with some of the worlds finest manufacturers, including cole hersee, general electric, furnassiemens, klocknermoeller, omron, and tycote connectivity. What is the main difference between a contactor and a magnetc motor started. Difference between a battery and a capacitor a motor starter is a combined device of contactor and over load relay. A relay is normally used in appliances below 5kw, while a contactor is preferred when the appliance is heavier. Load capacity contactors are used in control circuits with both low and high ampere capacity that is between 15a to 12500a.
Motor protection and control contactors and overload relays. Combine them with circuit breakers to meet machine safety standards and protect your motors against overloads and short circuits. Dec 11, 2017 differences between relays and contactors rsp supply. Much like a relay, a contactor is an electrically controlled switch. Ssrs, however, consist of electronic parts with no mechanical contacts. A general purpose motor control contactor may be suitable for heavy starting duty on large motors. Contactors are used for loads that have high voltages, high currents, or both. Contactors typically have multiple contacts, and those contacts are usually but not always normallyopen, so that power to the load is shut off when the coil is deenergized. Note1 in extension type, the digital empr is calibrated with combining the display. 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. Abbs thermal overload relays are suitable for threephase or. Difference between contactor and relay compare the.
Contactors electromechanical relays electronics textbook. The only difference between them is their power rating. Main difference between contactor and starter electrical. This problem occurs when the overload relays do not stay closed. Most relay coils are intended to operate on voltages that range from 5 to 120 volts ac or dc. Both these devices are used for similar purposes and hence people are often confused about the difference between a contactor and a relay. Relays are used in a wide variety of applications like electric power systems, home. Freedom series contactors and overload relays contactors 10 accessories 11 thermal overload relays 14 type 2 coordination selection procedure 16 technical data 18 dimensions 33 modular series contactors and overload relays contactors 38 accessories 40 technical data 42 dimensions 47 thermal overload relays 49 technical data 50 dimensions 54. The main difference between contactors and relays is the loads that they are meant to handle.
Compare up to 4 products and view the technical data and. Contactors and relays contactor relays moeller wiring manual 0208 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. Heating and cooling equipment require switching devices that are heavy duty and can operate for thousands of cycles. The lvmr distinguishes the difference between main power and regeneration power produced by a motor. Mar 12, 2017 mechanically, we have relays and contactors.
In comparison, the smaller electromagnets in relays are much easier to switch and doesnt require as much power. Powerxl de1de11 variable speed starters combine ease of use and. The relay is an automatic protective and switching device which is capable of sensing abnormal conditions in electrical circuits. Relays and contactors use a variety of technologies to switch signals and power. One possible scenario could be that excessive heat generated by a motor has caused the overload relay to trip, thus cutting off the power to the relay. Electrical controls for heating and air conditioning, contactors, relays, transformers, sequencers, time delays. What is the difference between relay and contactor answer pankaj relay. At es electronics, we pride ourselves on being among the industrys leading contactor and relay distributors.
It constantly monitors the dc bus voltage and sets the series brake automatically when it detects a power loss condition. The contacts are opened and closed by exciting this electromagnetic coil. Difference between relays and plcs electrical concepts. The plugin bases for lzslzx coupling relays are also available with plugin terminals. Dec 04, 2018 relays and contactors are electrically controlled switching devices. An electromagnetic coil is provided for opening and closing of contacts. Both have an external envelope to protect all the internal parts from the external environment. The class 9065 thermal overload relay is the most commonly used overload relay in. Relays, contactors, solenoids and for more information pdus. The basic principle of operation of the contactor and the relay are the same.
Controls contactors and contactor assemblies contactor. Contactors and protection relays schneider electric. Contactors can be obtained with coils designed for use on higher voltages than most relays. Here you will find our selection of top quality contactors and relays. Feb 07, 2010 relays and contactors are functionally same. These are operated to open or close the load contacts in response to one or more electrical quantities like voltage and current. Contactors are rated by designed load current per contact pole, maximum fault withstand current, duty cycle, design life expectancy, voltage, and coil voltage. They combine motor control and protection in a single. Electrically, we have transistors and integrated circuits. Electromechanical relays versus contactors digikey. Both of them are electrically operated switches used for control and switching of loads. Ssrs solid state relays use semiconductors for nocontact operation. 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. Devices of the 3th2 series are also available for connection with flat connectors and solder pin connectors.
Overload relays are often vulnerable to getting tripped. The contactor relays and the relays are available with screw terminals box terminals or with springtype terminals. Differences between relays and contactors rsp supply. Contactors are used for devices that pass more than 15 amps or loads of more than 3kw. This article will discuss the difference between relays and contactors. What is the difference between relay and contactor answer francesco the word relay comes from very old times and was used to call a set of horses that pull a car, when a relay of horses got tired they switch it for a fresh one. Hvacr electricalcms, 10 of 14, relays, contactor, and starters. Contactors need to switch larger contacts, thus they also have much larger electromagnets that draw significant amounts of power. Such relays are often used in transceivers which combine transmitter and receiver in one unit. Contactors and relays 67 tristate electrical supply. Contactor and relay are two terms often encountered when dealing with electric circuits.
Power rating of contactors are more than the relays. Overload relays are actually vulnerable to intermittent operations. Emt6 thermistor overload relay for machine protection. 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. Difference between contactor and relay since a contactor is required for a higher load, a relay is always cheaper than a contactor. Difference between contactors and relays electrical classroom. To turn things on and off, we need devices that are switchable by the application of a current or voltage. Contactors, and relays for hvac are available at wholesale and quantity pricing.