Understanding Timer Relays and Their Applications

14 February 2017
 Categories: , Blog

With the exceptions of electrical professionals and professionals in the construction industry, the mention of a timer relay does not ring a bell to a layman. And if it does, it might be construed to be a gadget used to measure time in relay races. But in reality, this is a gadget that provides useful functions in electrical systems.


The simplest definition of this gadget is that it is a switch that is operated electrically. The relay acts as an automated system that controls electrical circuits.


There are numerous types of relays. The distinctive factor that differentiates one relay from another is their mode of operation and specific function. For example, a mercury relay uses mercury as the switching element. Some common types of relays include:

  • Overload Protection Relay
  • Time Delay Relay
  • Machine Tool Relay
  • Multi-voltage Relays
  • Solid State Relay


A timer relay is used where there is need to control a circuit by a separate low-power signal. In addition, it can be used where it is required that only one signal controls several circuits. Compared to semiconductors, relays are more resistant to nuclear reaction, making them more suitable for control panels of radioactive machinery.

Generally, timer relays are used in OEM equipment and in industrial applications. OEM is a company that manufactures products that become part or subsystem of another company's product. In this context, a timer relay would be used as a circuit control mechanism in making products such as automation systems and digital computers.

There are types of very sophisticated relays that are used to protect electric power systems from the effects of power blackouts or any other trouble. In addition, some type of relays can be used to control both the generation and distribution of power.

In your home, relays find their application in your air-conditioning controls, dishwasher, washing machine, and refrigerator.


The application of timer relays provides protection to electrical systems and appliances. These protections are provided through the three primary functions of a relay – On/Off control, logic operation, and limit control. The On/Off control is used to limit a high-power load in your air conditioner. The limit control disconnects a motor that runs either slower or faster than the desired speed. The logic control is used when testing equipment.

Proper functioning of the timer relays ensures that you do not experience short circuits, overload, and other faults in electrical systems. In essence, timer relay provides your electrical system and appliances with a guarantee of protection form electrical-related faults.