Types of Relays and Their Functions Explained

Relay is a key component in electrical and automation systems. Below are the most common relay types and their specific applications.

1. Electromagnetic Relay

Used for switching control circuits, signal isolation, and general automation.

2. Intermediate Relay

Provides more contacts for interlocking and signal amplification.

3. Thermal Relay

Protects motors from overload using a bimetal strip mechanism.

4. Timer Relay

Provides ON-delay, OFF-delay, or cyclic timing functions.

5. Solid State Relay (SSR)

High-speed switching, no arc, no mechanical wear.

6. Protection Relay

Includes overcurrent, undervoltage, phase loss, leakage protection.

7. Pressure Relay

Switches based on hydraulic or pneumatic pressure.

8. Level Relay

Controls pumps or alerts based on liquid levels.

9. Speed Relay

Detects overspeed or underspeed conditions.