There are several models of relays, such as photoelectric relays, auxiliary relays, thermal relays, among others, but do you know what an electronic relay is and what is its application? In this article we will show all the components of an electronic relay and explain how electronic relays work, in addition to mentioning the main advantages and disadvantages of electronic relays.
What is an electronic relay?
When a relay is made up of an electronic system it is known as an electronic relay and operates in the protection of the power circuit against overload, blocking the passage of current if it exceeds a certain value.
Electronic relays can also be used to identify defects, signals, trigger alarms, open circuit breakers and also used to protect against voltage failure or phase failure, as consequently there will be an increase in current in these cases.
One of the basic properties of the electronic relay is its mixed composition: electromechanical and electronic. With this, the electronic relay can be activated with a low electric current and thus control circuits with a higher current from electronic devices, such as transistors and integrated circuits.
Operation of the electronic relay:
To understand how an electronic relay works, it is necessary to know its structure better. Therefore, the electronic relay consists basically of a coil, a magnetic circuit and contacts. The coil has an enameled copper wire, where its temperature can vary between 110 and 150 degrees, while its power can vary between 0.5 W and 2 W, reaching 6 W in power relay models.
The electric bonnet is capable of generating a magnetic field that drives the magnetic circuit. This magnetic circuit of the electronic relay is activated by electronic circuits, these circuits are activated by electric current and thus the coil is energized.
The electromechanical relay has a fixed and a mobile armature, where the magnetic field of the core provides the movements of two contacts. These parts are composed of special alloys or sweet iron, which prevent permanent magnetization, and the magnetic circuit generated by the coil is what activates the contacts.
These elements are responsible for opening or closing the circuit, when the current is interrupted, the magnetic field breaks up and the contacts return to their initial positions, which are defined as normally open (NO) or normally closed (NC) contacts.
The materials used in the manufacture of relays are generally silver, which is the most common material and gold, which is the most suitable for acting in a lower intensity current, in addition to these materials there is platinum, which has the greatest resistance to atmospheric agents. , arcs and tungsten, which is more suitable for currents under inductive loads and higher voltages.
If you want to know in detail how a relay works, we suggest this video below the Mundo da Elétrica channel. In it you will know all the components and understand their operation:
Advantages and disadvantages of the electronic relay:
The electronic relay, being an electromechanical device, has the advantage of being able to fully isolate the control circuit from the controlled circuit, performs complex switching functions and can also control currents in both directions, is resistant to surges and noise, does not cause leakage currents. The electronic relay, in addition to controlling any current intensity, can also operate with direct and alternating current.
The disadvantage of the electronic relay is the slow operation, arcs produced when the contacts are activated, noise and reliability. as it is an electromechanical system, they are heavy, expensive, bulky and the contacts are subject to repetition.
Electronic relay applications:
Electronic relays can be found in building automation, in electrical energy generation, transmission and distribution systems, in machinery and equipment in general. These devices are constructive parts of engine maneuvers, and for this reason that relays are very common in other environments such as homes, businesses and automobiles, operating in the control of electrical circuits, allowing the circuit to be turned on, off or undergo other changes, depending on how your connection is made.