Mar 25, 2015 difference between relays and contactor vaisakh tt. 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. Lets say a dc motor 20 a continuous current, 40 a peak surge is going full on in one direction. Unlike relays, contactors are designed with features to control and suppress the arc.
Today were going to talk about selecting a contactor for your application requirements. Activating the contact unit using electromagnetic attraction, which is produced when electric current exceeding the specified value flows to the electromagnet. In solid state relays, the inductor is replaced by a semiconductor element. A contactor combines 2 posts, without a typical circuit between them, while a relay has a typical contact that associates with an unbiased position. Relays and contactors use a variety of technologies to switch signals and power connections. Relays are often grouped together or with other components like.
My interlocking contactor on my 25hp rpc died this morning with a bright flash and a puff of expensive smoke. This page compares relay vs contactor and mentions difference between relay and contactor what is relay. The direct on line motor starter dol consist a mccb or circuit breaker, contactor and an overload relay for protection. Sirius 3ru thermal overload relays sirius 3rb electronic overload relays manual, 122017, a5e03656507420arsac004 9 introduction 1 1. This manual is intruduces the types, characteristics, functions and offers product.
Latching relays are the same as the singleside stable relays described previously except that the core, yoke, and armature are made from semihard magnetic material and there are at least two coils in the relay. La9f703 tesys f terminal shroud for contactor or relay 2p3p. On opening, there is rapid separation of the fixed and moving contacts in each contactor interrupter. 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. Relay blocks, both large and small, are located in the engine compartment. Battery contactor aka master relay, master contactor, master solenoid is a continuous duty relay meaning it can be turned on indefinitely.
Designed for continuous duty cycle, the c100 series offers heavy duty contacts to ensure long electrical life. Contactor vs relay electrical engineering stack exchange. Contactors and relays are two closely related terms leading to confusions and misinterpretations most of the times. 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. If you search for solid state relay vs mechanical relay dont rely on the content that comes from places that sell ssrs. The world of switches and relays american radio relay. Difference between contactor and relay compare the. Lets examine mechanical switching devices and become acquainted with how they look and perform. Contactors and relays 5 5 contactor relays contactor relays contactor relays are often used in control and regulating functions. Contactors are typically built for and used in 3phase applications where a relay is more commonly used in single phase applications. Shop our parts hvac online store for transformers, contactors, and relays hvac supplies and accessories. The main contacts of the contactor operate inside the vacuum interrupters the level of vacuum is extremely high. Definite purpose contactors, electronic overloads, enclosed manual motor starters.
It generally uses two circuits a control circuit and a power circuit. Definite purpose contactors hvac dp contactors elecdirect. These are operated to open or close the load contacts in response to one or more electrical quantities like voltage and current. Thermal overload relays for use with tesys k contactors.
Select required contactor by catalog number and replace the magnet coil alpha. Gt type overload relays are designed for the easy mounting directly to contactors or separately by using additional bases or brackets. Overload relays are part of the motor starter assembly of contactor plus overload relay. With a convenient mounting plate, the c100 offers ul class b insulation resistance. The easiest latching relay circuit to understand ever. Motor starters, contactors, and relays all operate on the same basic principle. To turn things on and off, we need devices that are switchable by the application of a current or voltage. Because of this, relays are often used as a middleman between the electronic circuit and the contactor. In motor starter, contactor controls the flow of electric current to the connected motor and repeatedly make and break. Our iec standard contactors feature snapon front mounted, as well as side mounted auxiliary. Contactor relays 2 and 3 pole relay cit relay and switch. A mercury relay, sometimes called a mercury displacement relay, or, mercury contactor, is a relay that uses the liquid metal mercury in an insulated sealed container as the switching element.
Also find hard to find transformers, contactors, and relay replacement parts. Electromechanical relay advantages an electromechanical relay has less resistance when switching current about 100 milliohms for. Overload relay, mt directly mountable to mc type contactor. Lastly, the mammoth relay on the far right is an automotive power relay, which is rated at 60 amps. Crc relay in conjunction with the directional unit and phase shifting mechanism of the type crp relay. How to size a contactor for any application springer. Series 300 nonreversing contactors for motor, actuator.
Last week we talked about the standard din numbers used on relays and the incredible utility they. Working of relayshow relay works,basics,design,construction. When the electricity of one store,ie, is turned off we apply a small signal to activate the contactor,a large box. The directional contacts are connected in parallel to torquecontrol a common overcurrent unit. Overheating of the contacts, generated at the moment they separate, causes formation of. The simplest form of motor starter for the induction motor is the direct on line starter. Both of them are electrically operated switches used for control and switching of loads.
At least, that is, in circles that dont have better things to do thandebate such things. Elecdirect stocks a wide range of four pole power contactors for rugged industrial applications. When a relay is used to switch a large amount of electrical power through its contacts, it is designated by a special name called as contactor. Electromagnetic contactor which can be opened by the thermal overload relay under fault conditions. Stardelta starters, open type version protection by thermal ol relay starters with mechanical and electrical interlock. The relay user should select contact materials, ratings, and styles to meet, as precisely as possible, the. A contactor is an electrical device which is used for switching an electrical circuit on or off. Power relay to small power contactor replacement thanks to their high switching capacity, the rif4 relay modules can be used in small power contactor applications. A wiring diagram is a streamlined traditional photographic representation of an electrical circuit. Iec contactors industrial power contactors elecdirect. For example, an overload relay can trip without a circuit breaker tripping. They are used in large quantities for the indirect control of motors, valves, clutches and heating equipment.
Contactor versus relay applications contactors are normally worked for and utilized in 3stage applications where a handoff is all the more generally utilized in single stage applications. Relay contact life relay contacts are available in a variety of metals and alloys, sizes and styles. They both are commonly used in industrial and commercial applications, and function in almost the exact same way. Therefore, this document is intended to describe about a few basic types of relays that are popularly used in typical loadcontrol.
Relay locations relays are located throughout the entire vehicle. What is the difference between a contactor and a relay. Devices switching more than 15 amperes or in circuits rated more than a few kilowatts. The contactor relays diler and dila fulfil this requirement.
In semiconductor testing, contactor can also refer to the specialized socket that connects the. Contactors electromechanical relays electronics textbook. Contactors, and relays for hvac are available at wholesale and quantity pricing. The difference between them is in term of their application and. This p roduces a retarding effect on motion of the rotor in either di rection. They protect the motor by monitoring the current flowing in the circuit. The contactor relay contacts themselves constitute a.
But where as contactor is a device which normally preferred. Air conditioner contactor wiring diagram inspirationa wiring diagram. What is the difference between relay and contactor answer shaheed. The forceguided coupling relay module ensures reliable signal exchange with feedback function between two systems. Some ssrs incorporate snubber circuits or zerocrossing detectors to reduce spikes and transients.
The control circuit regulates the flow of power and performs the basic switching operation using a small amount of current which can in turn be used to control a. Solid state vs electromechanical relays contactors. As known, contactor is used to switch higher capacity than relay. Manual motor starters, contactors and overload relays. Types cr, crc, crp and crddirectional overcurrent relays. Download magnetic contactor 1 pole relay wiring pdf. Air conditioning contactor wiring wiring diagram networks. Another important difference between the contactor and relay is, as the switching speed of the relays are.
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. The system is formed around basic units, which are equipped with. 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. Pressing either jog push button will deenergize the relay, releasing the closed contactor. This is to help protect the equipment downstream of the contactor from damage due to current. Contactor and relay are two terms often encountered when dealing with electric circuits. This relay will become warm during normal operations. 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. Definite purpose contactors are designed specifically for the hvac industry and are typically operated by a thermostat or manual pushbutton user interface. Abbs motor protection and control offering is among the widest on the market. In essence, to turn things on and off, we need devices that are switchable by application of a current or voltage.
Operating state set when current flows through coil a, the electromagnet made of. 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 1030seconds. Challenged by trying to find the right style of iec electrical contactor or control relay. Difference between contactor and relay difference between. Machinedesign com sites machinedesign com files uploads 2014 07 relay diagram. This means that the surrounding air and enclosure is enough to cool an emr, while many ssrs require additional. Modular system the modular system has many advantages for the user. Relays are classified into several types based on their functionality and application they are implemented for. Contactors are used in control circuits with both low and high ampere capacity that is between 15a to 12500a. The following lists the major categories available. Contactors, overloads and manual motor starters carlo gavazzi. The first three steps for selection will be the same. How to wire an air conditioner for control 5 wires the diagram below includes the typical control wiring for a conventional central air conditioning systemfurthermore it includes a thermostat a condenser and an air handler with a heat source. The basic principle of operation of the contactor and the relay are the same.
Contactors, overloads and manual motor starters minicontactors and overloads up to 20 amps or 7. The robust c100 series contactor relay is available as a 2 or 3 pole relay. Different types of relays and conactors contactor vs relay. 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. Relays are used in a wide variety of applications like electric power systems, home. Medium voltage products vcontact medium voltage vacuum.
By common usage, the term, contactor is applied to a special type of device that is functionally similar to the relay. A relay, in its most basic form, is a combination of a switch and an inductive element. So, if a relay has a same switching current with a contactor, which one to choose. Identify maximum amperage and maximum voltage going through contacts. Main difference between contactor and starter electrical. A relay is an electromagnetic switch that is used to turn on and turn off a circuit by a low power signal, or where several circuits. Semantics the differentiation between a relay and a contactor is a subject often debated in some engineering circles. Explained main differences between relay and contactor. Model c contactor a threephase starter b singlephase starter type. But there some relays can switch high current too, such as, some power relays can switch current beyond 100a, and there are contactors to switch only 160a. Both these devices are used for similar purposes and hence people are often confused about the difference between a contactor and a relay.
Battery contactor power in from battery power out to control unit or main bus. In this article, the basics of a relay like energized relay and deenergized relay are explained in detail. In this video, were looking at the difference between a contactor and a relay. Industrial relay system with screw connection for reliable switching of loads your advantages. The contactor is the relay to use when a circuit must support a heavy current load.
A contactor is controlled by a circuit which has a much lower power level than the switched circuit. From system integrator, oem, engineering consultant and distributor to panel builder and industrial enduser, our comprehensive range of motor starting solutions, products and services delivers the certainty of consistent quality and performance. Electrically, we have transistors and integrated circuits. Switching frequencyhour, according to acceleration time and load factor. The main difference between the contactor and relay is that, contactor is a high power device while relay is a low power device. Relay modules switch, isolate, and amplify signals reliably. Difference between a battery and a capacitor a motor starter is a combined device of contactor and over load relay. Download magnetic contactor 1 pole relay wiring free files. Top 7 difference between contactor and relay electrical4u. The main difference between relay and contactor is, relay is a low power device whereas contactor is high power device. Motor protection and control contactors and overload relays.
It shows the parts of the circuit as simplified forms, and the power and signal links between the tools. More specifically, circuit breakers and fuses are designed to detect when there is too much current in the circuit, while overload relays are designed to detect if a motor is overheating and will open the circuit if the motor gets too hot. In previous blog posts, we talked about the differences between iec vs. Also, the design, construction, working, applications, and also relay selection is explained in detail. Unit i introduction of relays a relay comprises of an electromagnet and a contact unit. Contactor relay coil voltage ranges from 24vac up to 240vac.
If you have some problem or fault while using this product, do refer to this manual. Contactor and relay free download as powerpoint presentation. Choosing between a relay and a contactor isnt really difficult. 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. Rated operational voltage of main contacts 690 v ac, ith 20 a, ie ac1 20 a690 v. Overload relays differ with the frame sizes in order to fit respective contactor. A mercurywetted relay is a form of relay, usually a reed relay, in which the contacts are wetted with mercury. Wiring diagram book a1 15 b1 b2 16 18 b3 a2 b1 b3 15 supply voltage 16 18 l m h 2 levels b2 l1 f u 1 460 v f u 2 l2 l3 gnd h1 h3 h2 h4 f u 3 x1a f u 4 f u 5 x2a r. Contactors and relays perform the same task and operate under very similar principles. Rather, the term, contactor is used to describe a type of device that is used very much in the same manner as a relay. Pdf magnetic contactor 1 pole relay wiring free files.
La9f703 tesys f terminal shroud for contactor or relay 2p. In addition to the simplicity which they offer in project engineering, panel building. Preventing arcing across relay contacts physics forums. The currentpolarized directional unit of the type crd relay operates on residual currents while the potential. A contactor is an electrically controlled switch used for switching a power circuit, similar to a relay except with higher current ratings.
The main difference between contactors and relays is the loads that they are meant to handle. Relays are basically switches which are primarily used for the protection of equipment. Relay vs contactordifference between relay and contactor. When a relay is used to switch a large amount of electrical power through its contacts, it is designated by a special name. Electra cloud is an industrial strength electrical cad software that works fully on the browser with builtin collaboration that allows you to access cad resources everywhere. Contactor relays dil two contactor relay series are available as a modular system. By doug wifb hat could be more ordinary than a switch. If the current rises above a certain limit over a certain period of.