Why are relays important? Why is there such a wide variety of relays?
Relays have always been an integrated part of all forms of communication and power infrastructure, but with the increased usage of closed control systems in automated applications there has been a constant growth and change in the usage of relays. Over the years, all industrial components including relays have constantly changed to the following effect:
Relays have undergone constant miniaturisation based on two aspects. The fact that their usage has changed from just switching power circuits to being used as switches in communication circuits and hence a reduction in the ‘load’ or ‘power’ they need to switch. Also, changes in material science and manufacturing techniques have enabled the relays to be built smaller with better housings and contacts. As a matter of fact, in the case of electronic relays, there is no physical contact and coil mechanism to enable switching. The switching is conducted entirely through a semiconductor switch.
When it comes to relays in specific, they are now able to switch at far higher speeds and with minimum power loss. Semiconductor or Electronic relays of course have become the norm when it comes to extremely high switching rates.
The number of operations that a relay can now undertake has also increased significantly on account of the fact that the relays are built with far superior materials and the fact that they need to switch much smaller loads. Also in case of electronic relays the expected life is extremely high as there is no physical switching involved.
With the above said there cannot exist a modern automation system without the use of relays and since each system may have its own specific need, the choice of relay becomes a critical function.