WHATS IS CONTACTOR?

A contactor is an electrical device which is used for switching an electrical circuit on or off. It is considered to be a special type of relay. However, the basic difference between the relay and contactor is that the contactor is used in applications with higher current carrying capacity, whereas the relay is used for lower current applications. Contactors can be field mounted easily and are compact in size. Generally, these electrical devices feature multiple contacts. These contacts are in most cases normally open and provide operating power to the load when the contactor coil is energized. Contactors are most commonly used for controlling electric motors.

There are various types of contactors, and each type has its own set of features, capabilities, and applications. Contactors can break current over a wide range of currents, from a few amperes to thousands of amperes, and voltages from 24 VDC to thousands of volts. In addition, these electrical devices come in varying sizes, from hand-held dimensions to sizes measuring a meter or yard on one side (approximately).

The most common application area of the contactor is high-current load. Contactors are known for their capability to handle currents of over 5000 amperes and high power over 100 kW. Heavy motor currents produce arcs when being interrupted. These arcs can be reduced and controlled using a contactor.

The following three are crucial components of the contactor:

Coil or Electromagnet: This is the most crucial component of a contactor. The driving force that is required to close the contacts is provided by the 1- coil or electromagnet of the contactor. The coil or electromagnet and contacts are protected by an enclosure.
2-Enclosure: Just like the enclosures used in any other application, contactors also feature an enclosure, which provides insulation and protection from personnel touching the contacts. The protective enclosure is made from different materials, such as polycarbonate, polyester, Nylon 6, Bakelite, thermosetting plastics, and others. Generally, the open-frame contactor features an additional enclosure, which protects the device from bad weather, hazards of explosion, dust, and oil.
3-Contacts: This is yet another important component of this electrical device. The current carrying task of the contactor is done by the contacts. There are different types of contacts in a contactor namely, contact springs, auxiliary contacts, and power contacts. Each type of contact has an individual role to play.

Operating Principle of a Contactor:The current passing through the contactor excites the electromagnet. The excited electromagnet produces a magnetic field, causing the contactor core to move the armature. A normally closed (NC) contact completes the circuit between the fixed contacts and the moving contacts. This permits the current to pass through these contacts to the load. When current is removed, the coil is de-energized and opens the circuit. The contacts of the contactors are known for their rapid open and close action.

The life expectancy of a contactor or its “contact life” is one of the biggest concerns of a user. It is natural that the contacts are being opened and closed more frequently, the life of the contactor will decrease. The opening and closing of the contacts create an electric arc, which generates additional heat. The continued production of these arcs can damage the contact surface.

Furthermore, the electrical arcs cause pitting and burn marks, which eventually blacken the contacts. However, the black deposit or oxide on the contacts make them even more capable of conducting electricity efficiently. Nevertheless, when the contacts get worn out and corroded to a large extent, then it is necessary to replace them.

Thus, the faster the contact closes, the quicker the arc extinguishes. This in turn helps to increase the life of the contact. The latest contactor versions are designed in such a way that they close very quickly and energetically. This causes them to slam against each other and produce a bouncing action as they rebound. This action is known as contact bounce. The contact bounce phenomenon creates a secondary arc. It is not only important to close the contacts quickly, but also to reduce the contact bouncing. This helps reduce wear and secondary arcing.

[dumbuyaelbowmusa]

You have added to my low experience as a technician, you guys are so good to such educative stuff, love it

[felipea]

I'm a dyslexic learner. This visual aid/video is very helpful. Thank you.

[gsp]

Thanks for a very informative and well explained video.
Now I understood how my contactor for my drillpress works, or does not work in my case.
The coil is defective, I would have never found out without this video.
A coil is much cheaper than changing the whole thing. 👍

[victorpaula]

Thank you for this video. The fact that you are using an interesting software to show how a contactor works it's a good way to understand this device.

[janettelanuiki]

I like the 3d cutaway! I’m freshening up on trying to get a maintenance job at a data center for a company that is well known around the world and I have to say (as a visual learner) this was much more informative than many other videos that I have watched

[InstrumentCalibration]

Great animation that makes the explanation simpler and interesting

[HostelHumour]

Finally understood what a Contacter is. Thanks. Nice work. 👍

[insoleafptyptd]

Really enjoyed the video. Great animation. Clear and concise description of functional operation and connections to the contactor. Would have been nice to show the start/stop button connected with thermal relay. Well done. May be worth explaining how the coil is able to operate off an AC source as most people would be familiar with energising a relay coil with DC and not AC in the case of the contactor.

[MarondromaRock]

I have very much enjoyed this video it was very specific and helpful. Could you please also make a video on how to make a 3 Phase generator, automatic changeover switch. There really isn't any very well described versions on the internet.

[Techno-Universal]

Some fancier contactors have inbuilt over current protection so it’s like it doubles as an over current circuit breaker. Generally when those contactors are tripped the button will pop out instead of being flush with the case and it disconnects the solenoid in that tripped position so it cannot be reactivated by whatever is controlling it until someone pushes in the contactor to manually reset it’s breaker.

[AliDINÇER-dq]

This is a good explanation. Thank you so much. You can tell electronic components(relay, transistor, etc.) and tell industrial devices. Your videos are simple and short. This is also good. It would be best if you continued like this. 😊

[MrSingh-enio]

Very help Video thanks for sharing 🙏🙏❤️

[asoteico]

Greatest 101 video about contactors. !!!

[digitaria]

Keeps explaining contractors and motors like this please until the this area of electrical installation and engineering is completely covered

[Zellaman]

Thank you so much for this informative video and we want more if these clear videos

[ahbmiho]

Thank's from Algeria, the explain is good!

[hawaslimoti]

Thank you for this video.
Can you please explane how it protect the motor .thankfully

[nrreno]

I cannot thank you enough for the visual guidance, very helpful

[bradwendica]

Now the electrician has a very well supply with knowledge, unlike during my era, I know nothing but because of my interest to know how to be an electrician, I perseverse more until I was hired in the power plant and passed also the board examination as master electrician, I was well versed familiar with, forward/ reverse, multi speed, reduced voltage starter, wye/ delta, coltrolled in more than one area, etc.

[PiChipinge]

Brilliant and very helpful. Simply put too