Ever heard of the term “contactor” in the field of electricity and electronics? From the name alone, you can imagine it is a device that works by coming into physical contact with another.
Generally, contactor is a switch that can be turned on or off by an electric current. They are commonly used in power plants, breakers, and substations.
Contactors are frequently used to control the flow of alternating current (AC) electricity to motors, generators, and other devices. Frequently they control the flow of power on AC motors. Contactors are typically designed for one-half or three-phase circuits which usually work with reversing contactors.
This blog post will teach you everything you need to know about reversing a contactor.
What is a reversing contactor?
While there are ordinary contactors, in this case our focus is on reversing contactors. Reversing contactors are used to reverse the flow of current in a load.
Contactors are designed to be used in applications where there is a constant flow of current, and then suddenly the current must be reversed. These devices will turn on when they sense that the voltage has reached a certain level and then they will close a switch to complete the circuit.
The most common use for reversing contactors is in industrial applications where heavy machinery such as conveyor belts or cranes require electricity, but only when they are activated. When power is not needed, the contactor can simply be switched off and prevent any unnecessary power consumption.
How do reversing contactors work?
From the definition, let’s now look at the working principle of a reversing contactor. The word “reverse” should give you hints on how the device works to deliver its functionality or performance.
As we have already defined, a reverse contactor reverses a 3-phase motor using contactors. This implies that if the motor is moving in a particular direction, the device will change just by using the contactors.
How does this happen? You may wonder.
When the motor is on, it will be running or rotating in one particular direction. So when the motor has reached a certain speed, if we want to increase its rotation speed, we will have to increase the voltage applied to the motor.
This is done by using more power from the power source. As more voltage is applied, the motors will be rotating faster and faster until it reaches a high speed. At that time, if we want to slow down or reverse the rotation direction of this motor, we will have to decrease voltage. If you do that, it will be possible for you to stop this motor by stopping its current flow.
Then here comes the reversing contactor. Once the contactor is engaged, the direction in which the motor is rotating changes immediately. It will start rotating in the opposite direction. This explains the whole ‘reverse’ shebang.
Components of a reversing contactor
To further cement your understanding of reversing contactors, let’s look at the key parts and components that make up this device:
Well, these are among the main components of a typical reversing contactor. There are two types of contacts, namely, fixed contactors and rotating contactors. The difference between the two lies in how they interact with the rotating motor. A fixed contactor is a component that is fixed in place and moves with the motor while a rotating contactor is a component that moves with the motor and remains stationary.
The contactors will dictate whether your reversing contactor is engaged or not. They come in different power ratings. They include 55W contactor, 75W contactor among other power options.
Hall Effect Sensor
The Hall Effect sensor, also known as Hall-effect sensor (HES) or Hall effect device (HED) is a device used to detect magnetic fields. It uses a metal ring that surrounds an electromagnet to determine which way or direction the magnet is moving. The metal ring contains an array of tiny magnets that line up in three dimensions along its length.
The assembly kit of a reversing contactor comprises different components designed to execute diverse tasks. These components include wiring rails, and electrical interlock. The wiring rails ensure that the contactor can be connected to the electrical wiring systems.
The electrical interlock is used to ensure that the contactor will not engage when it is not supposed to. The electrical interlock has a close connection with the reversing contactor. The electrical interlock serves as an extra measure of ensuring that the reversing contactor will not engage when it should not do so. This is achieved by using a relay and a switch that can be switched on or off without affecting any other parts within your electrical system .
The wiring of a reversing contactor has two main purposes. The first purpose is to allow power to flow into the contactor. This allows the contractor to be able to engage or disengage when necessary.
The second purpose of the wiring is for safety reasons. This is used in case of an emergency in which you may need to disengage the contactor from its position.
The base plate is the main part of the contacts. The base plate has a contact surface on its top side. This contact surface is used to engage with the relay’s contacts. The base plate also has a series of holes that allow wiring to pass through it. The design of the base plate also guarantees safety and stability of the reversing contact. It also provides physical protection to some extent.
These are also vital components of the reversing contacts.The mechanical interlocks are used to ensure that the contactor will not engage with the wrong contacts. This is done by using a switch and relay that can be switched on or off without affecting any other parts within your electrical system .
Do you know that reversing contacts also have switches? Yes, they do. These switches are used to provide a second method of controlling the contactor. The auxiliary switch can be used to control the contactor when the main switch is not available. The auxiliary switch can also be used to turn off the contactor completely.
How do you wire up a reversing contactor?
Wiring is an important step to undertake when setting up a reversing contactor. But, how do you do it? There are some simple steps you can follow.
-Connect the reversing contactor to a source of power.
-Connect the load side of the contactor to the load side of the circuit breaker or fuse box.
-Connect the neutral side of the contactor to a neutral point on your circuit breaker or fuse box.
-Connect one end of your cable to an electrical device and connect the other end to either side of your reversing contactor using a terminal strip, screw terminal block, or a connector that is compatible with these terminal strips and blocks .
-If you are using a screw terminal block or terminal strip, connect one end to an electrical device and connect it through another electrical device (such as a light switch) that is controlled by your main switch or auxiliary switch.
-If you are connecting a connector, attach it in place and then test it for continuity by touching one wire to the other.
It is important to use the proper connector on your reversing contactor. There are several types of connectors that can be used and each has a specific purpose.
-If you have completed all the steps above and tested your installation, test it again by making sure that it does not trip when there is no load on it (e.g., when there is no current going through it). This will ensure that all the wiring has been done correctly and there is no problem in your installation.
What are the advantages of reversing contactors?
Of what benefit are the reversing contactors? You may be wondering.
-Reversing contactors are very user friendly as they can be installed in a matter of minutes.
-They can be used for both AC and DC power applications.
-They are very reliable and give you the perfect protection for your equipment.
-They provide great value for money as they are more than just a simple switch.
– They are easy to install and maintain.
What are the applications of reversing contactors?
As we have seen, the main function of reversing contactors is to change the flow of a 3-phase motor. It is easy to point out the application areas of the reversing contactors based on their function.
Some of the reversing contactor applications include:
-Electricity generating plants.
-Power generation plants.
-Electrical power transmission systems.
-Electronic equipment and electrical appliances.
-Medical equipment and machinery.
-Telecommunications equipment and machinery.
-Air conditioning, ventilation, air purification, refrigeration and heat pump systems.
As long as the device will require a timely change of the direction of the motor, a reversing contactor will be necessary.
How to choose a reversing contactor
It is time to buy a reversing contactor. The market is flooded with a wide range of reversing contactors for sale. So, you are likely to experience some difficulties in choosing one.
You also don’t want to buy a reversing contactor that won’t work for you. I have compiled a few pointers that should help you choose the right reversing contactor for your project.
Consider the motor size
What is the size of the motor? In this context, the size refers to the number of poles in the motor. The motor size determines how much power should be dissipated. Once you know the size, you will choose the reverse contactor that will match the size of the motor.
Consider the voltage rating
The voltage rating is the maximum voltage that the contactor is capable of handling. If you will be using a reversing contactor in a DC powered system, it should have a voltage rating of at least 30 VDC. The voltage rating will also determine how much horsepower it can handle. A reversing contactor that works with 12 VDC can handle up to 1 horsepower while a reversing contactor rated for 30 VDC can handle up to 3 horsepower.
Consider the current rating
What is the current rating of a reverse contactor? The current rating refers to the maximum amount of current that can flow through the contactor. This is essential if you are using your reversing contactor as part of an AC power system or if you are powering it with other devices like an inverter, switch or an AC motor. In such cases, it is important to make sure that your reversing contactor has enough current handling capacity for what you want to do with it.
What is the ambient heat of a reversing contactor? This refers to how much heat the contactor is capable of dissipating. If you are going to be putting your reversing contactor in a very hot environment, it is important that you choose a contactor with enough heat dissipation capacity. Otherwise, your reverse contactor will overheat and malfunction.
This refers to how well a contactor is able to resist the flow of electrical current through it. The higher the insulation resistance, the better. A contactor with a low insulation resistance will have trouble withstanding the high currents that reverse contactors are designed for.
This refers to how well a reversing contactor is able to withstand external physical forces such as heat, vibration and shock. It also refers to how well it can withstand electrical shocks.
It is important that you choose a contactor that has an adequate electrical strength rating if you want your reversing contactor to last for ages.
As you can see, some of these factors are quite technical. So, it will be wise to let an expert help you with the selection.
I hope that with this guide, you will make smart choices when it comes to buying reversing contactors. Once you have made up your mind to buy reversing contactors in China, let ICRFQ help you. We are a reliable supplier of electronic components, including reversing contactors in China.
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