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. The german trade associations demand that, for control systems of powerdriven metalwork presses, the contacts of contactors must be interlocked. The first three steps for selection will be the same. 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. In semiconductor testing, contactor can also refer to the specialized socket that connects the device under test. Difference between contactor and relay difference between. In addition, these starters are available with contactors up to and including nema size 8. Difference between a battery and a capacitor a motor starter is a combined device of contactor and over load relay.
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. A contactor is an electricallycontrolled switch used for switching an electrical power circuit. Relay operation all relays operate using the same basic principle. 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. In process industries, a contactor is a vessel where two streams interact, for example, air. What are the contact surfaces of relays contactors, and starters made of.
This article contains a statement on the difference between the terms mirror contact and positively driven contact. The motor statrter is made up of a contactor with an overload relay attached physically and electrically to it. These relays are usually rated up to 10 or 15 amps. What is the difference between solidstate relays ssrs and contact relays. Difference between contactors and relays electrical classroom.
A relay is normally used in appliances below 5kw, while a contactor is. 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. Some contactors come with additional auxiliary contacts that may be either no or nc. The main difference between contactors and relays is the loads that they are meant to handle. What is the difference between positively driven contact. We offer the best quality hvac contactors and relays you can find. Relays tend to be of lower capacity and are usually designed for both normally closed and.
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. Introduction solid state relays ssrs and solid state contactors sscs are ideally suited for. What is the difference between relay and contactor answer pankaj relay. Here you will find our selection of top quality contactors and relays for the hvac industry.
In particular, large electrical gear as generators, motors and. These classifications include electromagnetic, solid state, high voltage, thermal relays, and so on. The difference comes if we see from the application perspective. A 90340 is a very common, versatile relay that many techs have on their truck so we will use it as the example. Contactors and relays are two closely related terms leading to confusions and misinterpretations most of the times. A summary of the difference between contactors, motor starters, relays and circuit breakers. Dec 04, 2018 relays and contactors are electrically controlled switching devices. Air products and controls multivoltage relay module. The more expensive the electrical gear, the greater the number of relays that will.
In process industries, a contactor is a vessel where two streams interact, for example, air and liquid. Definite purpose contactors hvac dp contactors elecdirect. The contactor relay contacts themselves constitute a considerable safety feature. Difference between contactor and relay since a contactor is required for a higher load, a relay is always cheaper than a contactor. A device for repeatedly establishing and interrupting an electric power circuit. Ssrs solid state relays use semiconductors for nocontact operation. If you see from the application point of view, you would have seen contactors placed in control panels of industrial motors. What is the main difference between a contactor and a magnetc motor started. Contactors are used in applications ranging from the light switch to the most complex, automated industrial equipment. A contactor is used for switching of motors, capacitors, lights etc, that drains very high current. The only difference is that relays are usually used for low. Cjx2 2510 lc1 d ac 25a motor magnetic contactor 3 phase 3p 3 pole 1no 220v 380v coil volt cjx2 contacts relay in contactors from pdf. 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. Pdf magnetic contactor 1 pole relay wiring free files.
As the torrent of water dried up for the first time in thousands of years, it revealed a horrific sight. 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. Definite purpose contactors and more building automation productions available to ship. Relays and contactors are electrically controlled switching devices. The difference between a contactor and a relay is the same difference as between a lake and a pond. Since interference free disconnection is impossible without an accessory.
Electrical contactors and relays hvac parts online. They both are commonly used in industrial and commercial applications, and. Selecting a solid state relay or a solid state contactor for startstop control of an ac motor by alessandro bosio, motion control business development manager, and paul bachman, fellow engineer crydom, inc. Contactors are used for devices that pass more than 15 amps or loads of more than 3kw. Jan 25, 2019 relays can be used for many different control applications including controlling fans, blowers, other relays or contactors, valves, dampers, pumps and much more. 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. Difference between ssr and contact relay faq india.
Ssrs are not very different in operation from contact relays electromagnetic relays. Relays and contactors use a variety of technologies to switch signals and power connections. 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. In addition to their current ratings and rating for motor circuit control, contactors often have other construction. Basically, its just two different names for the same thing. Therefore, this document is intended to describe about a few basic types of relays that are popularly used in typical loadcontrol. Sometimes called ice cube relays because they are small and square and with clear plastic like an ice cube. Many devices called relays use similar techniques and topologies. Main difference between contactor and starter electrical.
All dil contactor relays have doublebreak contacts. Contactors are used for loads that have high voltages, high currents, or both. The power circuit is engaged once the manual controller is activated by an operator. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The only difference between them is their power rating. Perhaps the most common industrial use for contactors is the control of electric motors. Load capacity contactors are used in control circuits with both low and high ampere capacity that is between 15a to 12500a. Relays and contactors are electromagnetic switches. Dec 11, 2017 much like a relay, a contactor is an electrically controlled switch. Selecting a solid state relay or a solid state contactor for. What is the difference between relay and contactor.
However, the basic difference between the relay and contactor is that the contactor is used in applications with higher current carrying capacity, whereas. Selecting a solid state relay or a solid state contactor. Electrical controls for heating and air conditioning, contactors, relays, transformers, sequencers, time delays. Feb 07, 2010 relays and contactors are functionally same. A relay is normally used in appliances below 5kw, while a contactor is preferred when the appliance is heavier. Class 14 esp100 starters use the same contactors as class 14 nema starters equipped with bimetal overload relays for nema sizes 00 through 4, but are supplied with a class 10, 20, or 30 esp100 solidstate overload relay. Contactors are used by electrical equipment that is frequently turned off and on opening and closing the circuit, such as lights, heaters, and motors. To turn things on and off, we need devices that are switchable by the application of a current or voltage. When a relay is used to switch a large amount of electrical power through its.
What is the difference between a contactor and a starter. Heating and cooling equipment require switching devices that are heavy duty and can operate for thousands of cycles. All moeller contactor relays have doublebreak contacts. Mar 25, 2015 this feature is not available right now.
Hence contactors are used in the switching of heavy loads and power circuits whereas relays are used in the switching of. Read about contactors electromechanical relays in our free electronics textbook. Jun 18, 2018 home about us news contactors vs relays. Power rating of contactors are more than the relays. A2 iec contactors relays a2 springer controls company 96074 chester road, yulee, fl 32097 904 2250575 fax. Definite purpose contactors are designed specifically for the hvac industry and are typically operated by a thermostat or manual pushbutton user interface. Much like a relay, a contactor is an electrically controlled switch. However, the basic difference between the relay and contactor is that the. 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 p roduces a retarding effect on motion of the rotor in either di rection. Unlike generalpurpose relays, contactors are designed to be directly connected to highcurrent load devices. A reader submitted a question through the ask chris form. They both are commonly used in industrial and commercial applications, and function in almost the exact same way. Unit 19 motor controls big book flashcards quizlet.
Heating and cooling equipment required high voltage controls that can endure thousands of cycles under extreme. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Difference between ssr and contact relay faq india omron ia. Motor starters, contactors, and relays all operate on the same basic principle. The magnetic starter is very similar to the magnetic contactor in design and operation. At kele we make it easy to find the right relays and contactors product. Generally, relays are smaller than contactors, just as ponds are generally smaller than lakes. What is the difference between a contactor and a relay. Difference between contactor and relay compare the. The more expensive the electrical gear, the greater the number of relays that will generally be used. It leaves out any physical differences, or standards. Contactors and relays perform the same task of switching a circuit. Understanding relays page 4 autoshop, all rights reserved. What is the difference between relay and contactor answer pankaj.
Selecting a solid state relay or a solid state contactor for startstop control of an ac motor. Both have the feature of operating contacts when the coil is. Contactors electromechanical relays electronics textbook. Contactors and relays page contactor relays 52 contactors dil, overload relays z 58 contactors dil 514 overload relays z 520. Contactors are used by electrical equipment that is frequently turned off and on. Relays can be used for many different control applications including controlling fans, blowers, other relays or contactors, valves, dampers, pumps and much more. Ive expanded the original question from what are the differences between relays, contactors and motor starters. Here you will find our selection of top quality contactors and relays. Class 14 esp100 starters use the same contactors as class 14 nema starters equipped with bimetal overload relays for nema sizes 00 through 4, but are supplied with a class 10, 20, or 30 esp100 solid. It has at least a single pair of three phase input and output contacts. Contactor vs relay electrical engineering stack exchange. Contactors can be field mounted easily and are compact in size. Whatever the application, the function of the contactor is always the same. Breakdown voltages coil rating coil voltage rating all terminals 60 hz rms contact material electrical life mechanical life nominal open max.
Relays are classified into several types based on their functionality and application they are implemented for. Switches, circuit breakers, and contactors are used to control what parts of an electrical system are energized or deenergized. Ssrs, however, consist of electronic parts with no mechanical contacts. Te relays, contactors and switches can be used anywhere in production lines, robotics, lifts, control panels, cash machines, motion control systems, lighting, building systems, solar, hvac, cars, trucks.
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