Different types of relays pdf

Relays and contactors use a variety of technologies to switch signals and power connections. Standard mini iso relays types below are two popular standard mini iso relay configurations. A wide variety of different types of relays options are available to you, such as general purpose, auto. Different types of relayss like overload protection relay, solid state and contactor relay etc. When the relay s coil receives sufficient voltage, its relay contact switch closes, turning the device connected to it on. Concept and working of different types of fuses protection. Ot trip oil temperature trip wt trip winding temperature trip bearing temp trip etc.

Pdf on apr 19, 2016, vladimir gurevich and others published. Use time, current and a combination of both time and current are three ways to discriminate adjacent overcurrent relays. This is because the induction disc characteristics of the overcurrent relays inverse characteristics are not amenable to simple mathematical analysis. With hinged relays, the armature of the electromagnet rotates around a fulcrum. These relays are employed as auxiliary relay, control relay, over current, under current, over voltage, under voltage and impedance measuring. Types and revolution of electrical relays introduction. Overcurrent relays types based on operating time characteristics, normally defined by the time vs. In the tutorial, introduction to relay, i have discussed the basics of relay. 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 circuit with a high amount of current. A power system consists of various electrical components like generator, transformers, transmission lines, isolators, circuit breakers, bus bars, cables, relays. A control relay is an electrical component that opens or closes a switch in order to allow current to flow through a conducting coil, with the.

Puzzled by the seemingly endless types of relays roaming around. These overcurrent relays need to coordinate with each other such that the relay nearest fault operates first. Types of relays the relay may be defined as an electrical device interposed between the main circuit and the circuit breaker in such a manner that any abnormality in the circuit acts on the relay, which in turn if the fault is dangerous then it causes the circuit breaker to isolate and so to remove the faulty element. Based on operation mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical. Implementation of out of step relays to protect generators 3. Electromagnetic attraction type induction type solid state relays numericalmicroprocessor based relays insulation monitoring relays gas. The following groupings will be used in this technical guide. Overcurrent relays overcurrent relaying is the simplest and cheapest type of protection used for protection of lines, transformers, generators and motor. Our book i show the different types of relays used in hvacr and also what components are mistaken as relays. Knowing the differences and understanding what to look for can be a huge help when deciding on the right relay for your build. Jun 08, 2019 power system protection relays can be categorized into different types of relays. A control relay is, in essence, a switch that is controlled by electrical current. Basically, types of protective relays are analoguebinary signal converters with measuring functions.

This type of relay uses one coil to control one switch with two contactsthere are four total contacts on this relay see figure 22. Hybrid relays are a combination of the best of both relays with contacts and relays without contacts. In this article we will learn about different types of. Different types of relays power system protection youtube.

In contrast to electromagnetic, reed, and thermal relays, solid state relays have no moving parts. For feeder protection, there would be more than one overcurrent relay to protect different sections of the feeder. Depending on the operating principle and structural features relays are of different types such as electromagnetic relays, thermal relays, power varied relays, multidimensional relays, and so on, with varied ratings, sizes and applications. Relays are used in many type of industrial applications. In addition to them there are different types of protective relays available in the industry. Electromagnetic relay working types of electromagnetic. Different types of relays, their construction, operation. The overcurrent relays, even though simplest of all types of electromechanical relays, are the most difficult static relays. In addition to having different operating types, relays can have their contacts arranged in various configurations depending on the use.

This p roduces a retarding effect on motion of the rotor in either di rection. These latching relays consist of 1 or 2 coils and have no default. An example of an ideal relay application is having one electrical signal setup to control several circuits, allowing complete isolation of electricity between the controller and the controlled circuits. The size of a iso standard mini relay is a 1 square cube.

Relays are the control switches that operate with lowpowered electrical signals controlling most types of circuits. Understanding relay in electronics with different types of. Implementation of outofstep relays to protect generators 3. Electrical and electronic switching as well as protection systems use different types of relays reed, thermal realay etc that employ both ac and dc supplies. Different types of relays used in protection system and their. The evolution of protective relays begins with the electromechanical relays. These relays are used in applications where there is a need to limit power dissipation and consumption. Relays are electrically actuated devices that act as switches. When the voltage is shut off, the relay s switch opens, turning the device connected to it off. Concept and working of different types of fuses protection from short circuit damages a.

In the olympic games, there are several types of relay races that are part of track and field. How relays work relay diagrams, relay definitions and. Different techniques are used to measure the period of coincidence. Generally speaking, there are four types of terminals in a relay. Relays are switches that open and close circuits electromechanically or electronically. In order to protect them from atmospheric protection they are safely kept inside a vacuum or inert gas. Electromagnetic relay working types of electromagnetic relays. Different types of relays and conactors contactor vs relay. As relay diagrams show, when a relay contact is normally open no, there is an open contact when the relay is not energized.

A relay race is a racing competition where members of a team take turns completing parts of racecourse or performing a certain action. Aug 31, 2018 attraction armature type relay is the most simple both in construction as well as in its working principle. Different types of relays mechanical, ssr, internal or external what are relays. There are many different types of relays used in todays world of electronics, and the properties of each determine what type of relay is used in which device. Not a pure hurdles event, the steeplechase combines distance running and a different form of hurdling. Track and field events hurdling, relays, multisport.

Jun 25, 2015 50 protective relay types current or voltage balance relays two basically different types of currentbalance relay are used. Different types of relays mechanical, ssr, internal or external. Relay races are common in running, orienteering, swimming, crosscountry skiing, biathlon, or ice skating usually with a baton in the fist. Relays are classified into several types based on their functionality and application they are implemented for. Types of relays and relay driver circuit buchholz relay. Types of protective relays basic construction different. Different types of relays mechanical, ssr, internal or. When two different materials are joined together it forms into a bimetallic strip. Therefore, this document is intended to describe about a few basic types of relays that are popularly used in typical loadcontrol.

Apr 28, 2017 different types of relays depending on the operating principle and structural features relays are of different types such as electromagnetic relays, thermal relays, power varied relays, multi. It generally uses two circuits a control circuit and a power circuit. The actuating quantity of an overcurrent relay is a current. Electromagnetic relays are those relay which operates on the principle of electromagnetic attraction. The different types of solid state relays include reed relaycoupled relays, transformer coupled relays, and photocoupled relays. You can choose from a wide range of relays but do you know what type to use in your project. Latching relays latching relays are electromechanical switches that are used when the switch needs to remain in its last position after the electrical current is turned off. In this article we will learn about different types of relay and what to use in you circuit to get the desired result. This is a fully detailed article the basically focuses on the the basics of relay including its pins configurations, its functions, types, working principle and many other things. These types of relays have been given more importance in the contacts.

I hope you have enjoyed the tutorial and i am sure you will appreciate my efforts. While the list of automotive relays below is not exhaustive, its a great start to seeing the options available. Following the introduction the general application of the different types is described after which typical applications are given complete with all the different wiring diagrams and tables listing all the individual ratings of the five different relays. Based on operation mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical relay. The timeline of the development of protective relays is shown below 1900 to 1963 1963 to 1972 1972 to 1980 1980 to 1990.

This impedance or corresponding distance is called the reach of relay. Power system protection relays can be categorized into different types of relays. All the relays react to voltage or current with the end goal that they open or close the contacts or circuits. Other than the electromagnetic relay there are many other types of relays which work on different principles. Read more about different types of protective relays and function of protective relays. Control relays are an extremely important electrical part, and they play a vital role in todays electronic devices. How relays work relay diagrams, relay definitions and relay.

Attraction armature type relay is the most simple both in construction as well as in its working principle. Testing and maintenance of protective gear, protection against surge. Many types of automotive relays exist to meet the demands of various applications. These types of electromagnetic relays can be utilized as either magnitude relay or ratio relay. Types of protection relays are mainly a based on characteristic. Though these types of relays have a very low switching current and voltage ratings, they are famous for their switching speeds. What is relay and different types of relays pdf elprocus. A relay is essentially a switch that is operated electrically rather than mechanically. This spst relay has one pole, with one contact a simple switch. Learn what is a relay, how a relay works, how it is designed and constructed and what are the different types of relays based on their working. Unit i introduction of relays a relay comprises of an. Types of protection relays are mainly based on their characteristic, logic, on actuating parameter and operation mechanism. Testing and maintenance of protective gear, protection against surgesurge absorber, surgediverter.

The magnetic field then uses for opening and closing the switch and for performing the mechanical operation. Protective relays work in concert with sensing and control devices to accomplish their function. Both relay types are frequently provided in one relay case and are actuated by the. The variables such as current, voltage, phase angle or frequency and derived values obtained by differentiation, integration or other arithmetical operations, appear always as analogue signals at the input of the measuring unit. Definition of protective relay a relay is automatic device which senses an abnormal condition of electrical circuit and closes its contacts. The relay is designed to operate when the actuating quantity equals, or exceeds, its pickup value. Iso micro relay types below are two popular micro iso relay configurations. An example of an ideal relay application is having one electrical signal set up to control several circuits, allowing complete isolation of. Relay race, also called relay, a trackandfield sport consisting of a set number of stages legs, usually four, each leg run by a different member of a team.

Types of relays there are different ways to classify relays. Based on the production of actuating torque, one may be called the overcurrent type and the other the directional type. Distance relays are designed to respond change in current, voltage, and the phase angle between. A contactor is an electrically controlled switch that is designed to be used for the opening and closing of an electrical power circuit. Relays are basically switches which are primarily used for the protection of equipment. Over the past decade it upgraded from electromechanical to solid state technologies to predominate use of microprocessors and microcontrollers. In this article, the different types of relays like overload protection relay, solid state relay, solid state contactor relay, buchholz relay, mercury wetted relay and many more are explained with diagrams. There are different types of relays including electromagnetic relays, latching relays, electronic relays, non. Under normal power system operation, a protective relay remains idle and serves no active function. Apr 29, 2017 many types of automotive relays exist to meet the demands of various applications. Different types of fuses a brief idea of the different types of fuses and their working is given here.

Well youre in luck as we decided to take a look into 5 common relay types in order to simplify this seemingly daunting topic. For example, steeplechasers cant glide over their hurdles, which stand 914 millimeters 3 feet high for men, but more importantly cant be knocked over because theyre thicker and heavier than standard hurdles and fill the entire track, rather than just one lane. One main difference between them is electromechanical relays have moving parts, whereas solid state relays have no moving parts. These classifications include electromagnetic, solid state, high voltage, thermal relays, and so on.

Power system protection relays can be categorized into different types of. There are four common types of relays that we briefly discuss each of these relays has only solenoid coil, but a varying number of power contacts. Although there are various relay designs, the ones most commonly found in low voltage auto and marine applications are electromechanical relays that work by activating an electromagnet to pull a set of contacts to make or break a circuit. Voltage restraint over current relay b based on logic. In my earlier post i have alreaady explained the working of relays, and their design and construction. Semiconductor elements transmit and cut the signal or power and contacts are used to supply the power for the relay. Well, sometimes is hard to choose, especially if youre not sure which model you need or how a specific one works. Relays control one electrical circuit by opening and closing contacts in another circuit. These contacts in turns close and complete the circuit breaker trip coil circuit hence make the circuit breaker trip.

All the relays respond to one or more electrical quantities like voltage or current such that they open or close the contacts or circuits. Relay races take the form of professional races and amateur games. Types of relay based on the principle of operation. Types of electrical protection relays or protective relays. It is a type of a magnetic switch which uses the magnet for creating a magnetic field. Nonpolarized relays nonpolarized relays do not use a permanent magnet in their. Many devices called relays use similar techniques and topologies.