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Different Types of Electrical Relays and Their Uses

What are Relays?

To begin with, let us first try to understand the term in-depth. They are used as the primary protection as well as switching devices in almost all of the control processes or any other equipment. All the relays that are present respond to one or more electrical quantities such as current or voltage, in a way that they open or close the contacts or circuits.

You can also say that it is a switching device, as its basic functionality is to isolate or change the state of any electric circuit from one state to another. If you want to differentiate between them, the first thing that you should keep in mind while doing so is how they function and for what purpose are they being used. You can differentiate them on the basis of – protective, reclosing, regulating, auxiliary and monitoring relays.

Now that you know on what basis can one differentiate between them, below are some of the types of electric relays and their functions-

1) Protection relays – According to Institute of Electrical and Electronics Engineers (IEEE) defines protective relays “Relays whose primary function is to detect defective lines or apparatus or other power system conditions of an abnormal or dangerous nature and to initiate appropriate control circuit action”.

Their basic functionality involves- detect the problem and then try to solve it by measuring the electrical quantities that are present in the power system, and it is seen that it acts differently when in a healthy condition and differently when its in intolerable condition. Its major duty is to protect its customers and equipment such as electrical switchboards.

2) Solid State Relays– This kind of relay is used to perform the function of switching without moving any parts. In SSR, the control energy required is much lower when you compare it to the output power that is needed by this relay. It, therefore, results in power gaining higher momentum when compared to the electromagnetic relays. You can bifurcate SSR into –

Reed relay coupled SSR
Transformer coupled SSR
Photo-coupled SSR, and so on.

3) Contactor Relay– With the help of a contactor, you can single-handedly stand on your own as a power distribution device or act as a partner. For those of you who don’t know where to use it, then you can easily find them in application varying from the light switch to even highly complicated automated equipment that is used in different industries. You can easily find one that is placed in electrical equipment, and you have to regularly turn it on or off- such as lights, heaters, and motors.

4) Electric Relay – They are used to electrically operated switches, and they come in different shapes and sizes, and power ratings. Moreover, you’d be surprised to find out that relays have either single or multiple contacts that comes within a single package and consists of larger power relays that are mainly used for high current or mains voltage switching applications that are known as contractors.

5) Differential RelaysA differential relay is defined as the relay that operates when the phasor difference of two or more similar electrical quantities exceeds a predetermined amount.

In conclusion, these were some kinds of electrical relays and their advantages. If you want to know more about these products and want to invest in them as well, there are many options available in the market today.

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