Time Delay Relays

Time delay relays are special types of electrical relays which delays an electrical contacts actuation. It is used to control the operation of its connected electrical circuits. Time delay relays are designed both for different application field and provide the protection for equipment and components within circuits.

Application Fields

Time delay relays are widely used in different application fields, such as lighting control, motor control and alarm systems. In lighting control, time delay relays are used to control the period when the lights are to be turned on and off. In motor control, time delay relays are used to delay the switching on of the motor for a certain period of time to make sure the motor is properly started. In alarm systems, time delay relays are used to ensure that any alarm signal is alarmed after sufficient period of time.

Working Principle

Time delay relays work by using a mechanism of either a mechanical or an electronic timer. The timer is programmed or set in such a way so as to adjust the delay period according to the requirements. It is most commonly used to delay the start-up of an electrical circuit or to delay the shut-off of an electrical circuit. The timer uses a certain type of input control and triggers the relay to switch after the predetermined set time is completed.

The timer mechanism can be based on electro-mechanical, electronic or electromechanical components depending on the time delay relay type. An electromechanical time delay relay is the most widely used type. It comprises a mechanical spring driven timer motor that is connected with the relay contact system. The motor is activated by a voltage source, and it rotates a cam attached to the electrical contacts. The cam\'s rotation determines the amount of time delay before the contact changes from open to closed or vice-versa.

An electronic time delay relay works the same way, but uses electronic components to generate the time delay and control the contacts which make it more precise and reliable. Electronic time delay relays are widely used in medical, industrial and commercial equipment as they are more reliable and consistent.

Conclusion

Time delay relays are an important part of many electrical systems. They are used to control the operation of many electrical circuits and provide the protection of equipment and components inside the circuits. Time delay relays use either a mechanical or an electronic timer mechanism which enables them to delay the start-up and shut-off of an electrical circuit. Moreover, they can be set to adjust the time delay according to the given requirement of the specific application.