In common term, a relay can be defined as an electromechanical device and is widely used for switching or breaking the electrical path called circuits. Currently, there are many types of relays available in the market, and these types are mainly derived from two primary types of relays such as electromechanical relay (EMR) and solid state relay (SSR).Thanks to the advanced technologies by making these two relays a Hybrid Relay is formed which overcomes the issues faced by both EMR and SSR.
All You Need to Know About Relays
Before proceeding to know about the hybrid relay, let us understand some basics about a relay, a device which is widely used in all types of electrical and electronic products used in homes as well as in large industries. A relay is generally known to be an electromagnetic switch consisting a coil or armature, a spring, and a electrical contact. As discussed earlier this type is known as EMR as it produces an electromagnetic field for its switching. On the other hand, SSR is an advanced type of relay which contains few solid-state elements like a diode, transistor, or FET which are combined with the moving contacts to establish a connection or to disable the current path.
Let us now study about both EMR and SSR and their merits and demerits. According to the experts EMR is considered to be highly reliable and are cost effective since it uses few parts in its construction. Also, this type of relay consumes less power when used in the electrical circuits. However, it has few downsides as this relay can produce arcing at the time of the contact due to the sudden surge of electrical current like the flood gates used in the dams.
We all know when the flood gates are opened in a dam or reservoir, the initial pressure will be high as the water reaches the lower level. In the same way, when high current is passed when the relay is switched on, the surge current produce a sudden arc which later deposited as a carbon particle in the relay switch. This reduces the life span of the EMR.
On the other hand, the SSR deploys solid state elements which can easily replace the EMR. This relay is silent and lat longer than the EMR type. However, SSR, when used in the circuit, generate heat and hence waste some power in the process. Also, this type of relay needs some colony system which adds up the cost.
It is here, the role of hybrid relay plays a critical role by using both EMR as well as SSR in order to eliminate the demerits of each type. With the introduction of hybrid relays designers can able to achieve extremely reliable switching, so has to improve the overall efficiency of the relay operations at the circuits wherever they are needed. By using both the EMR as well as the SSR in parallel higher efficiency is achieved. By this arrangement, the SSR is used in the initials switching and gets isolated after a period, and then the switching is controlled by the EMR. With this set up the aspect od heat, as well as arching, is eliminated. A hybrid relay does not need a heat sink at all which reduces the overall cost.
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