What is an electromechanical relay?

Relay is an electrical device that enables the control of electrical and electronic circuits. Depending on the design, a relay can operate as an electromechanical (electromagnetic) or semiconductor relay. It is an essential component in industrial automation, device control systems, and protection systems. It allows switching of high-power loads with minimal energy consumption in the control circuit, ensuring the safety and reliability of the entire system.

What is an electromechanical relay?

Electromechanical relay is a device composed of several basic parts: a coil, an armature, movable contacts, and a protective housing. It works on the principle of an electromagnet – when current flows through the coil, it generates a magnetic field that attracts the steel armature, causing the contacts to close or open. This allows control of the load circuit using a low-power control circuit.

Electromagnetic relays provide galvanic isolation between the control and load circuits, enhancing the safety of electrical and electronic devices. Their ability to switch high-power loads makes them suitable for industrial systems, automation installations, lighting systems, and electric motors.

Construction of an electromechanical relay

An electromechanical relay consists of several key components:

1. Coil – generates a magnetic field when voltage is applied. The coil can be powered by direct current (DC) or alternating current (AC), depending on the type of relay;

2. Armature – a movable element that opens or closes the contacts;

3. Contacts – can be normally open, normally closed, or changeover;

4. Housing – protects the components from external factors.

The magnetic field generated by the coil current attracts the armature, changing the state of the contacts. This simple yet effective operating principle allows electromechanical relays to control high-power devices with minimal energy consumption in the control circuit.

Principle of operation of an electromechanical relay

Electromechanical relays operate on the principle of an electromagnet. When current flows through the coil, it creates a magnetic field that attracts the movable armature. This movement closes or opens the appropriate contacts, allowing current to flow in the load circuit.

The relay operates in two states – energized and de-energized. Depending on the design, it may have normally open, normally closed, or changeover contacts, enabling on/off control of devices. Some relays also have timing functions that delay the switching on or off of the load, which is particularly useful in industrial automation.

Types of relays

Several basic types of relays are available on the market:

• Electromechanical (electromagnetic) relay – a classic type where an electromagnetic coil controls a set of movable contacts. It allows safe switching of high-power circuits using low-voltage signals;
• Solid-state relay (SSR) – uses electronic components such as transistors or triacs to switch circuits without moving parts. It is characterized by high durability, shock resistance, and fast operation;
• Time relay – has delay-on or delay-off functions, used in automation and control systems;
• Types of contacts – normally open (NO), normally closed (NC), and changeover (CO), allowing the relay to be adapted to specific applications.

Each type has its advantages and disadvantages – classic electromechanical relays are reliable and easy to service, while solid-state relays offer longer life, faster operation, and resistance to vibration.

Applications of electromechanical relays

Electromechanical relays are widely used in various fields of electronics and automation:

• Industrial automation – controlling motors, pumps, and other high-power devices;
• Lighting control – switching lighting circuits, including LED lighting;
• Protection systems – monitoring current and voltage in electrical circuits;
• Industrial equipment – controlling power supply and machine protection;
• Consumer electronics – switching circuits in electronic and electrical devices;
• Home automation – controlling low-voltage circuits in smart systems.

Electromechanical relays allow control of high-power loads with minimal energy consumption in the control circuit, improving the efficiency and safety of the entire system.

Advantages and disadvantages of electromechanical relays

Electromechanical relays have many advantages:

• high reliability in industrial applications,
• ability to control high-power circuits with low control current,
• galvanic isolation between control and load circuits,
• simple construction and ease of maintenance,
• various contact configurations for wide applicability.

Disadvantages include:

• presence of moving parts that wear out over time,
• limited switching frequency compared to solid-state relays,
• larger dimensions compared to modern solid-state devices.

Summary

Electromechanical relays are key components in automation, industrial electronics, and control systems. With a coil, armature, and movable contacts, they enable safe switching of high-power circuits with minimal energy consumption in the control circuit. They are used for controlling motors, lighting systems, protection circuits, and smart home automation. They are reliable, easy to service, and offer various contact configurations, making them adaptable to any application.

Electromechanical relays available in the DACPOL offer ensure reliable and safe circuit switching in automation, electronics, and energy systems. We encourage you to explore the full range of models suited for various industrial applications.