Contactors

Whether you’re looking for industrial contactors to provide power to electric motors, or you’re in need of a contactor to ensure your air conditioner works all summer long, our extensive range of contactors has everything you need to help you get the job done.

As leading electrical contactor suppliers, we have a whole host of contactors from leading brands in stock and ready to ship today.

What are contactors?

A contactor is an electrical device that is used for switching a circuit on or off. It is often considered to be a type of relay. However, where a relay is used for lower-current applications, contactors are used in applications with higher current-carrying capacity.

Contactors are most commonly used for controlling electric motors and lighting systems but can be employed in any device that is frequently turned off and on. There are various types of contactors, and each type has its own set of features, capabilities, and applications. From uses in basic light switches to complex applications such as controlling electromagnets, contactors are a highly versatile piece of equipment and come in varying sizes, from hand-held dimensions to sizes measuring a yard plus.

How do contactors work?

Designed to be connected to devices with a high current load, contactors incorporate spring-loaded contacts that make or break power supply lines to a load. A normally closed (NC) contact completes the circuit between the fixed contacts and the moving contacts. This permits the current to pass through these contacts to the load. When the current is removed, the coil is de-energized and opens the circuit. The contacts of contactors open and close very rapidly to assist with arc suppression, ensuring the contactors’ ability to interrupt heavy motor currents with minimal damage over a longer life cycle.

The best way to diagnose if you need to replace a contactor is to use a multi-meter device that measures the flow of electricity. You may even notice that some of the contacts on the contactor may have become pitted and worn down – which happen naturally over time.

The average lifespan of electronic contactors can be anywhere from 5–10 years, if properly maintained.

What are the different types of contactors?

The most common types of contactors are magnetic and manual.

Manual controllers

The power circuit is engaged once the manual controller is activated by an operator. The switch of the manual controller is not operated remotely and is attached to the controller physically. Once activated, it carries the electricity to the load. Manual controllers are:

• Safe to operate
• Non-exposed encased unit
• Physically small in size
• Single-break contacts replaced with double-break contacts

Magnetic contactor

Magnetic contactors are the most common type of contactor used in industrial control applications. It is one of the most advanced designs of a contactor and can be operated remotely. Only a small amount of control current is required by the magnetic contactor to open or close the circuit.

• Safe to operate
• Square and boxlike
• Can be smaller than palm-size or over a yard in length
• In the absence of electrical current, the spring pushes the core away from the coil – breaking the connection

There are two standards for contactors: NEMA (National Electrical Manufacturers Association) and IEC (International Electrotechnical Commission). The differences between NEMA and IEC components are reflective of their size, speed, functionality, and power. As such they rate their components by different standards.

NEMA

• The largest trade association of electrical equipment manufacturers in the United States
• Standardized frame sizes
• Primarily North American Standard
• NEMA standard contactor sizes are designated 00, 0, 1, 2, 3, to 9

IEC

• Global standard
• Smaller than NEMA contactors and less expensive
• Range of sizes offered is more numerous than the 11 NEMA standards
• IEC contactors are ‘finger safe’
• Faster to react to overloads

Why choose RS for your contactors?

As electrical contactor suppliers, we stock leading manufacturers including Siemens, Schneider Electric, and ABB. We’re one of North America’s largest distributers of electronic equipment and can guarantee that products meet the highest industry standards.

You can search our huge selection of electronic contactors, accessories, and timers by the most popular, by manufacturer, or by price. If you already know which contactor you require, you can enter the product name or number into the search bar.

If you have any questions or can’t find the contactors you’re looking for, get in touch and speak to one of our friendly advisors today. You can also find advice and further information in our expert content hub.