
A contactor is an electromechanical switch designed to manage power flow in electrical circuits, especially those involving high-current applications. Functioning like a relay but capable of handling heavier loads, contactors are essential for activating a variety of systems such as motors, heating equipment, and large electrical loads. 

They are particularly useful in providing central control of extensive lighting installations in commercial settings like office buildings or retail complexes. Contactors operate by using a coil that, when energised, either opens or closes the circuit, efficiently controlling power distribution. This can be done independently or as part of a motor starter assembly, ensuring versatile application across various industries.

## **How Do Contactors Work?**

A contactor operates through an electromagnet mechanism. When the contactor's coil is energised, it generates an electromagnetic field. This field exerts a force on the armature—a metallic rod connected to the moving contact—pulling it towards the fixed contact against the force of a spring. This action closes the circuit, allowing electricity to flow through the contactor. The contacts remain closed as long as the coil stays energised.

When the coil is de-energised, the electromagnetic force dissipates. This causes the spring force to retract the armature, separating the contacts and breaking the circuit, returning the system to its off state. This rapid on-off capability is essential for applications requiring frequent and controlled power interruption.

Contactors can be designed to operate with AC, DC, or universal coils. All of which work with both AC and DC currents.

## **Types of Contactor Specifications and Ratings**

There are various types of contactors, and each type will have its own set of specifications depending on your application. Some key specifications are:

**Voltage Ratings:** AC Contactor or DC Contactor ranging from 12 V to 440 V.

**Functionality:** Reversing or non-reversing functionality.

**Utilisation Categories:** Typically categorised under AC3 for motor starting and AC1 for resistive loads.

**Pole Configurations:** Available from 2 to 10 poles, accommodating different circuit arrangements.

**Contact Configurations:** Various contact configurations.

**Compliance Standards:** All contactors adhere to IEC standards, ensuring international compliance and safety.

### **Magnetic Contactors**

Magnetic contactors are the most common type due to their operational efficiency and ability to function without manual intervention. These devices operate electromechanically and can be controlled remotely, enhancing both safety and efficiency. They require minimal current to actuate, making them energy-efficient choices for various applications.

### **Knife-Blade Switch**

Introduced in the late 1800s, knife-blade switches are among the earliest forms of contactors. Originally used to control electric motors, they consist of a metal strip actuated by a lever to make or break contact. While historically significant, their manual operation led to rapid wear and susceptibility to arcing, corrosion, and rust due to the soft copper construction and exposure to environmental elements. As motor technology evolved to require higher currents, the safety and operational efficiency of knife-blade switches diminished, leading to their gradual replacement.

### **Manual Controller**

Developed as a safer alternative to knife-blade switches, manual controllers feature several advancements, including encased units, compact designs, and double-break contacts that interrupt the circuit at two separate points simultaneously. This design allows for safer operation with higher currents in smaller spaces. Although manual controllers offer enhanced safety and efficiency, their requirement for direct manual operation limits their application compared to more modern automated systems.

## **Difference Between Contactor and Relay**

Contactors and [relays](https://au.rs-online.com/web/c/relays-signal-conditioning/relays/power-relays/) are both essential components in electrical circuits, but they serve different purposes based on the voltage and current requirements of the application. Contactors are typically used in high voltage applications where the load current exceeds 15A. They are larger in size, making them more suitable for handling higher power applications efficiently. Additionally, contactors are generally easier to maintain and are most often used in circuits requiring normally open (NO) contacts.

Relays, on the other hand, are used for lower voltage applications where the load current is less than 15A. Due to their smaller size, relays are ideal for compact systems and are commonly connected as normally closed (NC) contacts, providing a different type of circuit control. Relays also offer faster switching times compared to contactors, making them more suitable for applications where rapid switching is critical.

Find out more about how [contactors and relays have been implemented to enhance train operations in Australia](https://au.rs-online.com/web/content/discovery/ideas-and-advice/enhancing-train-operations-in-australia-dc-contactors-and-relays) here. 

## **How to Order Contactors From RS?**

[RS](https://au.rs-online.com/web/) offers a comprehensive range of high-quality electrical contactors from industry-leading brands including [Schneider Electric](https://au.rs-online.com/web/c/automation-control-gear/contactors-auxiliary-contacts/contactors/?applied-dimensions=4294965589), [Siemens](https://au.rs-online.com/web/c/automation-control-gear/contactors-auxiliary-contacts/contactors/?applied-dimensions=4294965546), [Eaton](https://au.rs-online.com/web/c/automation-control-gear/contactors-auxiliary-contacts/contactors/?applied-dimensions=4294966708), [ABB](https://au.rs-online.com/web/c/automation-control-gear/contactors-auxiliary-contacts/contactors/?applied-dimensions=4294967279), and Allen Bradley. We also stock a selection of accessories used to enhance the function of contactors including, Contactor Overload Relays, [auxiliary contacts](https://au.rs-online.com/web/c/automation-control-gear/contactors-auxiliary-contacts/contactor-accessories/), mechanical interlocks, and much more.

Business account customers enjoy free delivery on all orders over $40 (excluding GST), with a $10 delivery fee for orders under this amount. On the other hand, delivery is free for orders over $80 (excluding GST) for all private accounts and guest customers; a fee of $12.95 applies to smaller orders. 

## **Delivery Information for Australia**

Ensure your order is placed by 5 pm AEST from Monday to Friday to take advantage of next working day delivery for items available locally. Be aware that some regional locations may face longer delivery times, especially for orders requiring special handling such as those containing hazardous materials or oversized packages.

For detailed information on all our delivery services, including special options like same-day delivery and consolidated shipments, please visit our [delivery information](https://au.rs-online.com/web/content/support/all-articles/delivery) page. Our streamlined ordering process is designed to help you easily find and receive the right products swiftly and reliably.



Contactors

Contactors & Auxiliary Contacts

Automation & Control Gear

Electrical, Automation & Cables

Automation Signalling

Electric Motors

Industrial Robots

PLCs, HMIs & Industrial Computing

Process Control

Sensors

Solenoids

Cables & Wires

AV Cables

Cable Glands & Fittings

Cable Joints & Cable Sleeving

Cable Management

Cable Ties & Fixings

Computer Cables

Electrical Power & Industrial Cables

Networking & Coaxial Cables

Single Core Cable

Wire to Board Cables & Ribbon Cable

Enclosures & Server Racks

19-Inch Racking

Enclosures

Enclosures & Racking Components

Fuses & Circuit Breakers

Circuit Breakers

Earth & Lightning Protection

Fuse Holders & Accessories

Fuses

HVAC, Fans & Thermal Management

Air Conditioning & Fans

Air Conditioning & Heating Accessories

Building Automation

Electronics Heating & Cooling Components

Fan Accessories

Lighting

Fluorescent Lamps & Tubes

Light Bulbs, Lamps & Tubes

Light Fittings, Fixtures & Luminaires

Lighting Components

Torches & Inspection Lamps

Relays & Signal Conditioning

Relay Accessories

Relays

Signal Conditioners & Isolators

Switches

Capacitive, Magnetic and Piezo Switches

DIP & Rotary Encoded Switches

Domestic Installation Switches

Foot Switches & Components

Joysticks & Components

Key Switches & Selector Switches

Keyboard & Keypad Switches

Limit & Position Switches

Micro Switches & Detector Switches

Push Button Switches & Components

Rocker Switches & Components

Rope Pull Switches & Components

Rotary Switches & Components

Safety Enabling & Control Switches

Safety Interlock Switches & Components

Switch Disconnectors & Components

Toggle Switches & Slide Switches

Electronic Components, Power & Connectors

Batteries & Chargers

Battery & Charger Accessories

Battery Chargers & Power Banks

Non-Rechargeable Batteries

Rechargeable Batteries

Connectors

AV Connectors

Automotive Electrical Connectors

Backplane & Rack Connectors

Circular Connectors

IC Sockets & Adapters

Mains & DC Power Connectors

Network & Telecom Connectors

PCB Connectors & Wire Housings

Power Connectors

RF Coaxial Connectors & Adapters

Terminal Blocks

USB, D Sub & Computing Connectors

Wire Terminals & Splices

Displays & Optoelectronics

Display Modules

Fibre Optic Components

Indicators & Indicator Components

LED Lighting Components

LEDs - Light Emitting Diodes

Laser Modules & Components

Optocouplers & Photodetectors

ESD Control, Cleanroom & PCB Prototyping

ESD Control & Clean Room

PCB Etching, Preparation & Developing

PCB Handling

PCB Spacers, Pillars & Supports

PCB Tools

Prototyping Boards

Passive Components

Antennas

Capacitors

Crystals, Oscillators & Resonators

EMI Filters & Protection

Fixed Resistors

Inductors

Passive Components Kits

Rotary Encoders

Sounder, Buzzer & Microphone Components

Surge Protection Components

Variable Resistors

Power Supplies & Transformers

Power Supplies

Renewable Energy

Transformers

Voltage Converters

Raspberry Pi, Arduino, ROCK, STEM Education & Development Tools

Arduino Shop

BBC micro:bit Shop

Development Tools & Single Board Computers

ROCK SBC Shop

Raspberry Pi Shop

STEM Education

Semiconductors

Amplifiers & Comparators

Audio & Video ICs

Chip Programmers & Debuggers

Clock, Timing & Frequency ICs

Communication & Wireless Module ICs

Data Converters

Discrete Semiconductors

Interface ICs

Logic ICs

Memory Chips

Power Management ICs

Processors & Microcontrollers

Programmable Logic ICs

Sensor ICs

Mechanical, Fluid Power & Tools

Access, Storage & Material Handling

Ladders & Steps

Material Lifting & Loading Equipment

Storage & Shelving

Transit & Equipment Cases

Trucks, Trolleys & Lifting Tables

Adhesives, Sealants & Tapes

Adhesive, Sealant & Tape Dispensers

Adhesives & Glues

Sealants & Resins

Tapes

Bearings & Seals

Gaskets, Seals & Packings

Linear Motion

Rotary Bearings & Housing Units

Engineering Materials & Industrial Hardware

Anti Vibration & Levelling Components

Carbon Fibre & Felt Sheets

Castors & Wheels

Ceramic Materials

Channel Support Systems

Conveyor Components

Insulation Materials

Knobs, Levers & Handles

Metal Materials

Plastic & Rubber Materials

Polishing & Finishing

Shim Stock

Structural Systems

Fasteners & Fixings

Clips & Springs

Girder Fixings

Magnets & Magnetic Strips

Nails & Rivets

Nuts & Washers

Pins, Keys & Retaining Clips

Screws & Bolts

Sheet Metal & Panel Fasteners

Spacers & Standoffs

Wall Plugs, Fixings & Anchors

Hand Tools

Cable, Connector & Crimping Tools

Clamps & Vices

Hammers & Demolition

Knives, Scissors & Saws

Manual Grease Guns & Accessories

Measuring & Marking

Pliers & Cutters

Sanding, Filing & Polishing

Screwdrivers, Hex & Torx Keys

Spanners, Sockets & Wrenches

Specialist Tools

Staplers & Riveters

Threading Tools

Tool Kits & Tool Storage

Mechanical Power Transmission

Belts & Pulleys

Brakes & Clutches

Bushes & Collars

Electric Actuators

WEG Contactors

0 Products showing for WEG Contactors

Popular Searches

Related links