http://eletri.co/lide-dyt ???????? How to Read and Interpret Electrical Diagrams and become a recognized Maintenance Electrician. http://eletri.co/manual-de-eletrica ???????? Electrical Manual. . http://eletri.co/d120719 ???? Access and download the electric motor speed right now. And find out the real speed of the most used Three-Phase Electric Motor on the market with the most slip. It's free, don't miss the opportunity to acquire this knowledge. Have you ever heard of the zombie contactor? If you haven't, it's because it doesn't really exist... lol But what about a buzzing contactor? If you haven't heard of this, you've probably heard its buzzing. Most maintenance electricians who work with electrical controls have probably come across a contactor making this noise, this is even common in controls. But if you are called to perform electrical maintenance on a panel and when you get there, there is a buzzing contactor, do you know exactly what causes this defect, so you can start the maintenance? The first cause that I show you in the video is simple: the contactor may have a foreign object inside it, in its air gap. This object or dirt may be preventing the cores from fully touching each other, thus causing the noise. Second case… The short-circuit ring of your contactor may be broken, which causes the blades of the cores to hit inside the contactor, also generating the noise we are talking about. Third point, the voltage or frequency that the coil is receiving may be wrong. Voltage below the nominal, or a frequency outside of what the contactor demands, can also cause this buzzing. Fourth point… Oxidation. That's right, oxidation of the contactor core is also responsible for this buzzing. Rust or vermilion, for example, cause this type of defect. The fifth and final cause is if the contactor is controlling an electric motor, and when the motor starts, there is a voltage drop. Since the contactor only works correctly with the exact voltage, this can also cause the buzzing in its core. To learn more details about all of the points above, and even how to maintain some of them, just watch the video. I'm sure that if you come across this defect inside a panel that you are performing maintenance on, you will be much more confident about how to act. Be sure to download it and learn everything about the speed of the three-phase electric motor plus slip. Every electrician must be up to date with everything that involves the most widely used motor on the market. It's free. Enjoy ???? http://eletri.co/cta120719 A big hug. Everton Moraes and Sala da Elétrica Team. ⚡ Our FanPage ???? http://eletri.co/face ⚡ Our Blog/Site ???? http://eletri.co/blog ⚡ EletroFace PlayList ???? http://eletri.co/yteletroface ⚡ Everton Responde PlayList ???? http://eletri.co/yteresponde ⚡ Technical Videos PlayList ???? http://eletri.co/yttecnico ⚡ Safe Electrical PlayList ????http://aeletri.co/ytelsegura Our Courses: ⚡ Electrical Commands ???? http://eletri.co/ytcoel1 ⚡ Free CADe SIMU Course ???? http://eletri.co/ytcs. Music - Djlang59 - Drops of H2O (The Filtered Water Treatment ) - http://dig.ccmixter.org/