The Chief Brief: Relay vs. Contactor – What’s the Real Difference?

Relays and contactors are two electrical components that are often confused, which can lead to issues in a system if you choose one over the other. Both serve as electrically operated switches that can manage how current flows, but they are not interchangeable. Selecting the wrong component can have damaging effects on your electrical system. Stick with Chief to discover the real differences between relays and contactors.

Understanding the Relay (Small Signal, Big Control)

Electrical relays are electrically operated switches that use an electromagnet to manage the flow of electricity within a circuit. They operate on a smaller current which then in turn controls a larger one. When a small electric current passes through the relay coil, it creates a magnetic field that opens and closes a set of contacts. This capability allows relays to isolate certain parts of the circuit, control multiple circuits from one signal, or provide electrical isolation between systems. Relays are typically used for lower power control and signal switching applications.

While there are many different types of relays, Chief Enterprises partners with Hongfa, a global player and leading manufacturer founded in 1984, to supply relays suitable for various automotive and industrial applications. 

Chief’s focus is on product lines designed for maximum reliability and current management including:

• Size-Specific Automotive Relays: This includes various sizes required for vehicles and heavy equipment, such as Maxi Relays, Micro Relays, and Mini Relays (including Mini ISO Relays and Mini ISO Relays with Brackets)
• High Current (Power) Relay: Designed to manage higher current applications compared to standard relays, handling anything from a few amps up to hundreds.
• Solid-State Relay (SSR): Utilizes semiconductor devices for switching; they are quicker and more durable, making them ideal for high-speed tasks.

Hongfa, with its three research and development facilities, is constantly improving these designs. These specific relay types are ideal for applications across Medium & Heavy-Duty Trucks, Agricultural Equipment, Construction & Forestry Equipment, Marine, Power Generation, and Specialty Vehicles.

Understanding the Contactor (High Power, Heavy Loads)

Designed to manage high-power circuits, a contactor's main responsibility is to either start or stop the flow of electrical power to a load. Contactors are built to handle heavy currents and are often used to switch large loads such as motors or heavy machines. Compared to relays, contactors are generally larger, more robust, and can handle greater mechanical wear. They are built for high-current, high-voltage power applications, with ratings that range from several amps up to several thousand amps and voltage ratings up to 1000 V.

Chief Enterprises works with Altran Magnetics LLC to supply focused solutions for modern high-power demands, offering electrically controlled devices that are specifically designed to switch current on and off remotely using safe loads and voltages. These highly specialized DC contactors provide reliable remote switching for high-power systems, making them ideal for applications such as Electric Vehicles (EV), Renewable Energy, and Battery Disconnect Units (BDU).

The Real Differences: A Side-by-Side Comparison

From Relays to Contactors: Chief’s Guide to Choosing the Right Component

Choosing the right component for your circuit involves several key factors, including current and voltage ratings, the circuit’s purpose, and the expected durability and lifespan. For lower-current and lower-voltage control circuits, relays are typically the ideal choice; while contactors are built for high-current, high-voltage power applications that demand greater endurance.

At Chief Enterprises, we make that selection process seamless. As a leading distributor for premier manufacturers, we offer an extensive range of Hongfa Relays and Altran Magnetics DC Contactors. Our on-staff engineers provide direct technical support to help you choose the optimal component for your specific application. Partner with Chief to get the right solution for your circuit, every time.