Contactor vs Relay: What's the Difference?

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Contactors and relays are essential components that are used in electronic applications. Both are designed to serve as switches in electric circuits. They control the flow of electric current in their respective application areas.

In as much as contacts and relays appear to be the same or interchangeable, they are different devices. Unless you are keen on matters concerning electronics, you will end up choosing contacts in place of relays or vice versa. The results will be catastrophic if you choose the wrong device for your application.

The good news is we are here to give you the right information about these devices. In this article, we are going to do a complete breakdown of the differences between contacts and switches. By the end of the day, you will be in a perfect position to choose the right device for your application.

Definition

What is a contactor?

A contactor is an electromechanical type of switch whose core function is to control the flow of electrical current in a circuit. In most cases, contactors are used in high-power electric circuits.

The structure of a typical contactor consists of contactors, a coil, and a frame enclosure. Once the contactor is energized or acquires electric current, it will generate a magnetic field. The magnetic force that emanates from the field will attract the contacts to come together. In doing so, they will close the circuit hence allowing electric current to flow through the electric load.

Since contactors are ideal for high-power applications, the electric current in most cases is usually above 15 amps. They can handle an electric current of more than 5000 amps and power exceeding 10kW. Additionally, they have the full capacity to handle inrush currents, which are quite common in inductive load applications such as electric motors.

The material for the contactor is not only magnetic but also has high electric conductivity. This is because once the contactors come into direct contact, they should allow the smooth flow of current with minimal resistance.

The key function of the enclosure frame is to protect the components of the contactor. It is made of either plastic or metal materials and provides an ideal shield against external elements such as rough weather conditions and even physical forces.

What is a relay?

A relay is also an electromechanical device that is designed to serve a switch such that it can control the flow of current in an electric circuit. A typical relay has a coil that receives the electric signals and converts them into mechanical forces that trigger the contacts to determine whether an electric circuit should open or close.

Like contactors, relays also have an enclosure that protects the contacts and other sensitive components in the circuit.

Relays are commonly used in low-power applications. It can be used in any electronic application whose current is below 15 amperes.

Differences between contactors and relays

Now that you know what these devices are, let’s look at key areas that differentiate contactors from relays.

Current capacity

The first major difference is in their load capacities.  As we have seen, contactors have higher load capacity than relays. They are designed for high-current loads. This explains why they are mainly used in high-power applications. Relays, on the other hand, are designed for low to medium loads.

The design and construction of these devices are the main factors that determine their difference in load capacities.  If you are working on an application, you can gauge whether it is high-power or low-power. From there, you will choose the right device.

Switching mechanism

Contactors and relays also differ in terms of their switching mechanisms. While both control the flow of current in electric circuits, they use different mechanisms to achieve this goal. Take note that both use electromechanical mechanisms to switch the circuit. The main difference is in the design and construction of the contacts.

The switching mechanism in contactors is designed to handle high currents. Contactors have large contacts that can handle the current and also minimize the effects of electrical arcing that is caused by high currents.

On the other hand, the switching mechanism in relays is executed by contact contacts that can comfortably handle low current loads. The contacts are also lightweight.  A capacitor may be connected to the circuit to prevent inrush current in case of excess current.

Switching speed

There is a minor difference in the switching speeds of these two. Contactors are slightly faster than relays. This is mainly because they handle higher loads than the relays.

For the contractors, the switching speed ranges between 20-250ms, while the switching speed for relays ranges between 3-100ms.

Durability

The two types of switches have different lifespans.  Contactors have shorter lifespans than relays. This is mainly based on the factor that they handle higher power, which hurts the components that make up the switch.

Conclusion

Contactors and relays are vital components in the modern world of electronics. They play an important role in regulating the flow of power in systems. If you are looking for a component that will serve the same purpose as an electric switch, then you should consider narrowing down your options to either contactors or relays. They are likely to deliver more than you expect.

However,  you should take your time to analyze the differences between these two components. Keay areas of differences such as performance, switching speed, size design, and load capacity will help you choose one over the other. You will be able to tell which one is more suitable for your application area.

Once you have made up your mind, the next course of action is looking for the right source of either contactors and relays.  In most cases, it is from the best electronic component suppliers, especially when you want to buy contactors and relays in bulk.

This is exactly what you get when you choose ICRFQ. We are a reputable supplier of quality electronic components such as contactors and relays. As a global supplier, we have the full capacity to supply the components worldwide. All you need to do is contact us directly and we will deliver the right electronic components that you need for your application.