Auxiliary relays are electromagnetic switches designed to control other circuits by opening and closing contacts. They are often used in applications where a small control signal needs to operate a larger load, or where isolation between two circuits is required.

How Auxiliary Relays Work

Auxiliary relays consist of a coil and a set of contacts. The coil is connected to the control circuit, and when it is energized, it creates a magnetic field that pulls the contacts closed. This completes the circuit between the auxiliary relay and the load. When the coil is de-energized, the magnetic field collapses and the contacts open. This breaks the circuit between the auxiliary relay and the load.

Benefits of Using Auxiliary Relays

Auxiliary relays offer several advantages over other types of switching devices such as SSR (Solid State Relays), and MCB (Miniature Circuit Breakers):

• Isolation: Auxiliary relays provide electrical isolation between the control circuit and the load circuit. This can be important for safety reasons, or to prevent interference between the two circuits.

• Amplification: Auxiliary relays can amplify a small control signal to operate a larger load. This is useful in applications where a low-power device needs to control a high-power load.

• Control: Auxiliary relays can be used to control a load from multiple locations. This is useful in applications where the load needs to be operated from multiple control points.

Applications of Auxiliary Relays

Auxiliary relays are used in a wide variety of control applications, including:

• Motor control: Auxiliary relays are used to control the operation of motors. They can be used to start, stop, and reverse the direction of rotation of a motor.

• Lighting control: Auxiliary relays are used to control the lighting in buildings and other facilities. They can be used to turn lights on and off, dim lights, and create special lighting effects.

• Heating and cooling control: Auxiliary relays are used to control the heating and cooling systems in buildings. They can be used to turn the systems on and off, adjust the temperature, and create custom heating and cooling schedules.

• Security systems: Auxiliary relays are used to control the operation of security systems. They can be used to activate alarms, lock and unlock doors, and turn on lights.

Conclusion

Auxiliary relays are versatile devices that can be used to control a wide variety of electrical circuits. They are commonly used in industrial control, commercial building automation, and residential applications.

Frequently Asked Questions

1. What is the difference between an auxiliary relay and a contactor?

Auxiliary relays are typically used to control smaller loads, while contactors are used to control larger loads. Auxiliary relays also have a smaller physical size than contactors.

2. How do I choose the right auxiliary relay for my application?

When selecting an auxiliary relay, you need to consider the following factors:

• The load current that the relay will be switching
• The voltage that the relay will be operating on
• The number of contacts that the relay needs
• The type of mounting that the relay will be using

3. How do I wire an auxiliary relay?

The wiring of an auxiliary relay depends on the specific application. However, in general, the coil of the relay is connected to the control circuit, and the contacts of the relay are connected to the load circuit.

4. How do I maintain an auxiliary relay?

Auxiliary relays require minimal maintenance. However, it is important to inspect the relay periodically for signs of wear or damage. The contacts of the relay should also be cleaned periodically to ensure proper operation.

5. Where can I buy auxiliary relays?

Auxiliary relays can be purchased from a variety of sources, including electrical supply houses, online retailers, and manufacturers.