It is best to define contactors and relays as electrically charged devices that enable the electrical circuit to operate to its maximum efficiency. For this purpose, air contactors and a range of similar tools define the arc.
Because these switches are used on a single control panel, it can be challenging to determine the difference between relay and contactor. What are the specific characteristics of electrical contractors and relays? Describe the mechanism of electrical contractors and relays. We’ll find the answers to these questions and many more in the following few sections. This guide gives you details about contactor vs. relay.
Introduction to Contactors and Relays
A distinctive characteristic of electrical contractors and relays is that they operate on the same principle. To put it simply, both devices are solenoid switches that are operated by electricity to manage and tweak the electrical load. Their construction is nearly identical, illustrating many similarities between their working principles.
So, how do relays and contactors work, and what are the materials they are made of? Both relays and contactors have a top housing with a bunch of contacts. It is important to note that these contacts are usually open, but they may also be closed. As opposed to the top housing, the bottom housing of both these devices includes an excellent magnet and coil that is used to maintain and protect all the other tertiary accessories.
Contactor vs. Relay
Now that you know how a relay and a contactor work, it might be essential to know the critical differences between these devices. The primary difference between the two devices is how much electrical current they can handle. Since contractors are used to handling electrical loads with high voltages and currents, they have distinctive features in contrast to most relays.
To better understand the differences between both devices, review the following feature descriptions that sum up the devices’ roles and purposes.
The best definition of a control relay is a device that ensures that all contacts in a specific circuit can be operated even when conditions in the same or similar circuits change.
Conversely, contactors are devices whose primary function is to interrupt an electrical circuit when it exists in a typical environment.
The most significant difference between the two products is their size. A control relay has a relatively small size when compared to a contactor. Secondly, control relays carry less load than contactors due to their small capacity.
3. Power and Circuit Ranges
Contactors are ideally suited to carry electrical loads over 10 Amps, while control relays can only carry electrical loads of up to 10 Amps. Control relays are typically operated in single-phase circuits is precisely why control circuits are predominantly single-phase. In contrast, contactors are capable of managing a three-phase electrical load effectively.
4. Contact Types
The auxiliary contacts of relays and contactors are another crucial difference between them. An average contactor will have at least three power electrical contacts with some additional built-in contacts. In contrast, a typical control relay will have only two NO or NC-type electrical contacts. You will find control relays with open and closed contacts, but a typical contactor is designed to operate only with open contacts. Form A contacts are what they use instead of relay contacts.
5. The System ratings
Finally, as mentioned earlier, the most significant differences between the two devices are their system ratings and voltage control capabilities. Unlike conventional relays, which have a 250 V rating, a contactor will usually have a rating of 1000 V or higher.
Although the two devices are very similar, their sizes and structural features are the most significant differences. As relays are much smaller than contactors, their functionality, voltage, and capacity often differ from those of a contactor. The devices are not interchangeable since they perform different functions.
6. The capacity of the current switching
Essentially, a contactor is used to connect and interrupt higher voltages, while a relay is used for connecting and interrupting lower voltages. Currents of up to 15 amps can be switched by relays, along with relatively low voltage and current signals. The contactor is used to switch currents more significant than a few amps and power levels between several hundred and several thousand watts.
7. The Coil power
The coil power is the power needed to actuate the relay or contactor in watts. Contacts are actuated by the coil of a contactor and relay by a set amp-turns product. The amount of current, and therefore power, required is kept to a minimum by using many turns of fine wire. A contactor has a higher coil consumption than a relay.
8. The Arcing
The current may be interrupted and maybe arcing when the contacts are opened. Arcing can damage the switching device or reduce its life expectancy. An excessive switched current will increase temperature and contact arcing, degrading the device and shortening the contact life. Compared to relays, contactors generate more electrical arcs due to their high capacity to carry current.
Many relay designs with manual operators allow users to move the contacts from their normal position manually. Other relays have small lights or flags that indicate the position of a relay. Troubleshooting can be made easier with these features. A contactor does not have these features. Troubleshooting relays are straightforward.
Relay and Contactors Applications
The structure of both relay and contactor indicates that they have specific functions. For instance, relays are designed to be used in single-phase electrical circuits, ideal for single-phase applications. In an electrical network with at least three phases, you might want to use a contactor. Even though modern-day relays have a wide range of functions due to their multifaceted features, some of the primary applications are:
- Controlling and monitoring motors
- Various industrial applications
- Manage and control electrical loads
Although contactors come in a range of categories, their essential operation can be summarized as follows:
- They are used to start motors.
- To switch existing capacitor banks.
- To control and monitor lighting fixtures.
What is the best way to choose a contactor or a relay?
You might want to consider the following factors when choosing a relay or a contactor:
- A control relay is best suited to use in single-phase circuits with a maximum electrical capacity of 250 VAC and a maximum current capacity of 10 A.
- In a single to a three-phase electrical circuit with an electrical capacity requirement of 1000 VAC or higher, you might want to use contactors instead when the capacity is 9A or more fabulous.
- It will become easier for you to determine which device among the two best suits your needs when considering these essential aspects. Considering that both devices have specific and distinct functions, it is best to use the appropriate product for an appropriate environment because both devices have specific and singular features.