What type of contactor

It was difficult to manually open or close the switch quick enough to prevent arcing; as a result, the soft copper switches underwent corrosion, this process made them more vulnerable to dirt and moisture which led to rusting.

As years passed and technology began to advance, larger motors were developed. The larger the motors, the more currents they require to work. But it is extremely dangerous to operate such high current carrying switches, so these type of contactors were no longer efficient. Even though technology was continuously improving, the knife blade switches could not be fully developed due to the problems and risks of operational hazards and short life of the contacts.

After discovering the dangers involved with the use of the knife switchblade, engineers and researchers came up with another contactor device which offered better safety and a number of features that were not available in the knife blade switch.

The new design was called the Manual Controller. The new features added include:. Among the new features added, apart from the safety feature, the next most important feature of this new design is the addition of the double break contacts. These new contacts are designed to open the circuit in two places at the same time. So even in smaller space, it enables you to work with more current.

As the name implies, the double break contacts break connections such that it forms two sets of contacts. The button or switch of the manual controller is attached to the controller so it cannot be operated remotely. Once the manual controller is activated, the power circuit is engaged, and it carries the electric currents to the load. Due to its better efficiency and safety of operation, the manual contactors replaced the knife blade switches and even today; they are still being used, albeit not as much as in the s.

Related topics: How to choose right contactor for your motor. Relays, just like contactors, are devices that are used to open or close circuits electromechanically or electronically. Relays are not just switching devices; they are primary protection as well in most control processes or equipment.

All relays can be classified with one or more electrical quantities like current or voltage such that can close or open circuits or contacts. As mentioned before, a contactor is an electromechanical switch used primarily for opening or closing electrical circuits. A contactor is usually controlled by a circuit that has a lower power level compared to the switched circuit — for instance, a volt coil controlling a volt motor switch.

The major difference between both devices is that contactors are more powerful than relays, so they are used for high power applications. Contactors can be used in control circuits that have both high and low current capacity that is between 9A to A. Contactors are designed mainly for three-phase applications. However, relays are primarily designed for single-phase applications. Contactors are designed to handle high voltage applications and high voltage translates to more danger.

So, to prevent accidents, safety features such as spring-loaded contacts have been added to the device. Spring-loaded contact is a feature that prevents internal short circuit if the contactor gets into overload situations. Another safety feature on the device is the Magnetic Arc Suppressor. This feature helps to remove or reduce sparks formed when contacts carrying currents are separated. Differences between a contactor and a relay. Contactors are much slower than Relays when it comes to switching speed, so because of this, relays can be operated using electronic signals.

Contactors consume more power than relays because relays make use of smaller electromagnets than contactors. Because contactors are used for high current capacity applications, they are relatively larger and heavier than relays. Obviously, because of the difference in size, efficiency, and functionality, contactors are costlier than relays. The disadvantages of knife blade contractors are overcome using a manual contactor. Some of the features of these are,.

It operates electromagnetically that is it can be operated remotely, less amount of current is enough to make a connection and remove the connection. It is the most advanced contactor. What is the difference between a relay and a contactor? The size of the relay is small The size of the contactor is large Cannot be repaired Can be repaired 2.

What is a contactor used for? It is a switch used to switch high power load and protect the motor from external damage. A normally closed contactor can be represented as NC, which means the connection is made and the circuit is normally on.

Thus, this all about an overview of the contactor , it is an electrical switch used in electrical circuits like electrical motors switching circuits or capacitive switching circuits. They carry the high current to various parts of the circuit. They are operated by energizing electromagnetic coil inside it when the coil is energized the movable contacts move towards fixed contacts and close the circuit.

Here is a question for you, what is the function of a contactor? What is Contactor : Construction, Types and Applications. Share This Post: Facebook. They are designed for the contactors with self-extinguishing arc is drawn whenever the contact opens. They are specially designed to suppress electrical arching when there is switching in the DC circuit. After understanding the types, you will avoid selecting the wrong device for your applications.

Because the reason for contactor failure is usually the wrong product selection. Contactors have specific types for specific purposes. There are many types of contactors in electrical systems.

Below you will find different types of contactors that are used in the industry. A power contactor is an electrically controlled switch used for switching an electrical power circuit. Power contactors come in many forms with varying capacities and features. Generally, they switch high-capacity loads such as motors, heaters, and transformers. They are produced from 9A to A.

Power contactors are provided in either three or four power pole configurations with a variety of accessories, including auxiliary contacts, connecting links, interlocks, and bus bars. Most of the power contactors belong to the class of air-break. If coil power is removed, an arc is created as the contacts open. Air-break contactors extinguish the arc by separating the contacts by a sufficient distance.

Mini contactors are ideal for general-duty applications where small size and cost are key concerns. They can be used in special modular and compact applications. The small dimensions provide customers with high flexibility in use for applications up to 20 A resistive loads and motor loads up to 5. Generally They dissipate less heat and some models that have low coil consumption can directly actuate from PLC.

A mini contactor can be mounted on din rail or wall. Their accessory options are limited. You can use them on small machines, automatic doors, industrial kitchen appliances, and cleaning machines. It is always recommended to use a dedicated capacitor contactor for switching capacitor bank, which optimizes the switchgear cost and enhances the equipment life. Capacitor contactor are specially designed to meet the requirements of capacitor switching.

When capacitor banks are switched, the voltage associated with a low line impedance may produce high currents on the capacitors. These contactors are fitted with the front-mounted block of 3 early make auxiliary contact in series with quick discharge damping six-resistors-2 per phase to limit peak current to value within contactor making capacity such that normal rated capacitor current is carried by main contacts which, after closing, effectively short out the resistors.

You need capacitor contactors for power quality improvement projects. Their utilization category is AC6b. The bar contactor is a durable, open-type contactor used for switching very high AC and DC applications. Bar contactors are designed to cut out considerable electric arcs. They are extremely versatile and easily accessible for maintenance.