What Are Contactors and Their Different Types

Various industries, as well as basic daily devices, often rely on the use of electricity for operations. As most electronic devices are not intended for around-the-clock use, many are equipped with components used for halting the current. Considered a special type of relay, a contactor is a device used in electrical devices to switch the circuit on or off. When you are looking to control applications with high current carrying capacity, consider including a contactor in your circuit.

The main difference between a contactor and other relays is its ability to handle higher currents, so contactors are generally used for controlling electric motors. They are easily mounted, compact in size, and capable of breaking currents from a few amperes to a few thousand amperes. They can also break currents from 24 VDC to thousands of volts. Regardless of their applications, all contactors comprise three parts: a coil or electromagnet, an enclosure, and contacts.

The coil or electromagnet of a contactor is the most crucial component, acting as the driving force required to close the contacts. Surrounding the coil or electromagnet is an enclosure used to provide insulation and protection from personnel using the contacts. This enclosure can be made from any number of materials, including polycarbonate, polyester, Nylon 6, and many other options. Lastly, the contacts are used to carry the current, and many types of contacts are employed in a single contactor. These include contact springs, auxiliary contacts, and power contacts; each serves its own individual purpose.

When operating, the electric current passes through and excites the electromagnet or coil. The electromagnet produces a magnetic field or the coil extends, causing the contactor core to move the armature and complete the normally closed (NC) circuit between the fixed contacts and the moving contacts. This permits the current to pass through the different contacts and to the load. Once the current is removed, the coil is de-energized and the circuit opens again. The contacts are known for their rapid open and close action.

A few types of contactor devices exist with different purposes. The first contactor used to start and stop electric motors was the knife blade switch, that of which used a metal strip that would drop onto a contact when a lever was pulled. This design lost popularity as manually opening and closing the switch fast enough to avoid arcing, and higher current applications, created physical danger to operators. This led engineers to develop the manual controller for contactors. This design is safer to operate with no exposed unit and includes double break contacts for opening the circuit in two places at the same time. With the improved design, these devices are still used today. The final type of contactor is a magnetic contactor, which stands out from other designs in that it does not require human intervention; instead, this device operates electromechanically. With only a small amount of control current required by the magnetic contactor to open or close the circuit, this is the most common type of contactor used in industrial control applications.

To begin procuring any contactors for your electronic devices, look no further than Veritable Aerospace. We are a leading online distributor of contactors and other high-caliber part types from trusted suppliers around the world. With around-the-clock service, rapid lead times, and competitive cost savings, find out why loyal customers rely on us time and time again. Simply submit a Request for Quote form for any item(s) to receive an Instant Quote for your comparisons. Give us a call or email to get started today; we are readily available, 24/7x365!


March 15, 2021

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