Cómo Funciona un Relé ⚡ Qué es un Relé (Relevador o Relay)

What is a Relay and How Does It Work?

Introduction to Relays

• A relay, or contactor, is an electrical device designed to interpret input signals to abruptly generate or eliminate contact between two conductors in an electric circuit.

• Relays electrically separate the control circuit from the circuit being controlled, making them versatile for various applications like motors, compressors, heaters, and PLCs (Programmable Logic Controllers).

Importance of Electrical Separation

• The chapter discusses the significance of separating the control circuit from the load circuit. For instance, a sensor activating an LED may need to trigger more complex actions like starting a conveyor belt.

• Simply changing connections from an LED to a motor won't work due to insufficient current; higher voltages could damage sensitive components in the control circuit.

Functionality of Relays

• Relays solve these issues by allowing low-power signals to control high-power circuits without direct contact. The signal that previously activated an LED now controls the relay's operation.

• Electromagnetic relays consist of three main components: an electromagnet, a movable armature, and contacts. When current flows through the electromagnet, it generates a magnetic field.

Working Mechanism

• The electromagnetic coil creates a stronger magnetic field when wound into coils and enhanced by an iron core. This attracts the movable armature made of ferromagnetic material.

• As current activates the electromagnet, it pulls on the armature which then connects contacts in another circuit—closing it and powering devices like motors.

Types of Relay Configurations

• There are different configurations for relays; one common type is normally open (NO), where no current flows until activated. Another type is normally closed (NC), which allows current flow until activation interrupts it.

Understanding Relay Functionality and Applications

Modifying Circuit Controllers

• The circuit controller can be programmed to send an electric current when a belt needs to stop. However, if the battery fails or changes are needed, the motor may run continuously until resolved.

Relay Types and Energy Implications

• Choosing between normally open and normally closed relays affects energy consumption. For example, a normally closed relay is preferable for controlling a lamp that should remain on for 20 hours and off for 4 hours, as it only requires energizing for 4 hours.

Relay Configurations Explained

• Relays can be single-pole or double-pole; the number of poles indicates how many circuits one switch controls, while throws indicate different output connections. A double throw relay combines both functions.

Motor Direction Control with Relays

• Using a double pole double throw relay allows control over motor rotation direction by connecting terminals in such a way that changing the relay state reverses current polarity.

Limitations of Electromagnetic Relays

• While relays can separate circuits of varying voltages and currents, high voltage can ionize air leading to electrical arcs. This poses risks due to increased temperature at contact points.

Addressing Relay Performance Issues

• Electromagnetic relays experience contact bounce due to mechanical movement which may affect performance in high-frequency applications. Solid-state relays eliminate these issues as they have no moving parts.

Solutions for Improving Relay Functionality