About Relays and Contactors 

Contactors and relays are vital in electrical systems, acting as switches to manage power flow. Despite their similar basic functions, distinguishing between a contactor and a relay can be confusing. Both are used for load switching and are components of an electrical circuit that responds to the applied load. Choosing the wrong type of electrically operated switch for a specific application can lead to significant financial loss and damage to the electrical circuit. A thorough grasp of the basic principles and technical details of contactors versus relays is crucial for making well-informed choices in the design and maintenance of electrical systems.

What is a Relay?

Relays are the switches that aim at closing and opening the circuits electronically as well as electromechanically. It controls the opening and closing of the circuit contacts of an electronic circuit. When the relay contact is open (NO), the relay isn’t energized with the open contact. However, if it is closed (NC), the relay isn’t energized given the closed contact. However, when energy (electricity or charge) is supplied, the states are prone to change.

Relays are normally used in the control panels, manufacturing, and building automation to control the power along with switching the smaller current values in a control circuit. However, the supply of amplifying effect can help control the large amperes and voltages because if low voltage is applied to the relay coil, a large voltage can be switched by the contacts.

What is a Contactor?

A contactor is an electromechanical device that regulates the electrical current in high-power settings. It is composed of three primary parts: a coil, contacts, and a housing. The coil, when activated, produces a magnetic field that pulls the contacts together, closing the circuit and enabling current to pass through the electrical load it controls.

Operation of Relay and Contactor

A relay is a type of electromagnetic switch which is operated based on the current change in a circuit. When an overload condition is detected in a circuit, it will trigger the electromagnetic armature of the relay to close or open depending on the configuration.

The operating principle of the contactor is similar to the relay; the current flowing through the contactor energizes the electromagnet. When an overload is detected in the electrical circuit, the energized electromagnet then creates a magnetic field. This causes the core of the contactor to move the armature to an open position, thus cutting the flow of power in the circuit.

Applications of Relay and Contactors

Relays are developed to be used in various single-phase networks thus they have single-phase applications while the contactors are developed to be used in three-phase networks. Different kinds of relays are used in different circuits for different applications while some conventional applications of relays are:

• Automotive Applications
• Motor Control
• Industrial Applications
• Controlling Power Loads

Contactors have also different categories and while there are numerous applications of contactors, some common applications are listed below:

• Motor Starters
• Capacitor Banks Switching
• Lighting Control

Relay and Contactor Products 

 At ElectGo, we offer wide range of relay and contactor products from various brands. 

Frequently Asked Questions (FAQ)

1. Can I use a contactor in place of a relay?

While relays and contactors operate on similar theories, they are designed for specific uses in industrial circuits and are not interchangeable. 

2. What is the purpose of the contactor?

A contactor is an electrical switch that is designed to open and close a circuit repeatedly. It is typically used in applications that require the switching of higher currents, in contrast to standard relays, which are used for switching lower currents.

3. Do I need a relay or contactor?

It depends on your needs. Relays are used with electrical loads at a range of about 10 amperes or less, while a contactor load capacity is greater than 10 ampere.