What are time delay relays?

Time delay relays, also known as time-release relays, are control relays with a built-in time delay function. The main purpose of time delay relays is to start and stop currents from moving in the moving parts of electrical devices, such as coils and armatures.

Triggered in different ways, time delay relays can be used to minimise the amount of energy used to start industrial machines or to turn these off at pre-determined times.

Applications of time delay relays

Time delay relays can be found in several industrial applications, some of which include:

• Conveyor belts – time delay relays can control the starting and stopping of different conveyors at different times, so that items can be moved from one conveyor to another in proper time
• Lamps – many lamps use time delay relays to turn on and off at given times, for example, traffic lights used them when changing signal 
• Motors – some slow starting motors use time delay relays, allowing for less power to be used upon starting 
• Industrial machinery – time delay relays are often used in industrial machinery to allow for slower starts, thereby avoiding the excessive generation of energy 
• Safety applications – time delay relays can be used in combustion chambers or furnaces to avoid explosions and fumes

Types of time delay relays

The two most common types of time delay relays include:

• On-delay timers – these devices begin timing when input voltage is applied
• Off-delay timers – these devices accept the trigger when power is applied