Как подключить Трехфазный Электродвигатель 380 вольт через Контактор КМЭ. Схема пускателя двигателя.

#electrician #contactor #starter KME Contactor Construction and Repair    • Ремонт электромагнитного контактора (пуска...   This training video explains how to connect a three-phase asynchronous electric motor to a control circuit based on an electromagnetic contactor. I have a three-phase asynchronous motor. A cable is connected to the motor, which has a grounding conductor, which is connected directly to the motor housing. These three wires are the phase wires, yellow, green, and red, A, B, and C. For the motor to run, it needs power. This circuit breaker has three phases and a neutral wire, which is not needed yet. I'll try connecting the motor directly to the circuit breaker, and when I turn it on, the motor should start turning. I connect the phase wires from the motor to the circuit breaker. The grounding conductor is connected to the ground busbar. I apply power, and the motor starts running, then I turn it off. Although the motor operates with this connection, it's not a very good one. It has several drawbacks. For example, this control scheme doesn't allow for any automatic on/off control. But the biggest drawback is danger. Let's say I've turned on some mechanism, but suddenly the power goes out. The mechanism stops, and no one turns off the circuit breaker. And when the power suddenly reappears, mechanisms everyone had long forgotten about start moving, which can lead to problems. Therefore, the best solution is to use a magnetic contactor circuit. A contactor consists of an electromagnet whose magnetic circuit consists of a fixed and a moving part, or armature. And the electromagnet coil has terminals A1 and A2. Terminal A2 is duplicated for ease of installation, so we can use either one of these terminals—it doesn't matter. The fixed contacts are attached to the housing; I'm removing them now. Now you can see the electromagnet armature with the moving contacts. Let's begin assembling the power section of the circuit. First, connect the circuit breaker output to the input terminals of the electromagnetic contactor. Now the phase conductors are connected to the power contacts. And I'll connect the cable leading to the electric motor to the outputs of these contacts. Don't forget about protective grounding. I apply voltage. Now, if I mechanically close the contactor contacts, the motor will turn on. Next, I need to assemble the control circuit. I'll use a standard pushbutton panel with two buttons. My contactor coil is rated for 220 volts, so I can use any phase, and I'll take the neutral from my neutral busbar. I connect the blue wire to the A2 terminal of the coil, and the other end to the neutral busbar. Let's look at how the pushbutton panel is designed. The red STOP button uses a normally-closed contact. This wire, marked with a red dot, will supply the phase. While the button is depressed, the phase voltage flows through it and the jumper to the black START button, which uses a normally-open contact. When the black button is pressed, a phase voltage will appear on this wire, which will act on the contactor coil. Let's assemble the pushbutton control panel. I can connect this wire going to the red button to any phase; I'll connect it to phase C simply because it's closer. And I connect this wire coming from the black button to the A1 terminal of the contactor. I apply voltage. Our task is to pull up the contactor armature, just as we did manually. I press the START button. The contactor pulls up, and the motor starts turning. The Start button circuit includes a Stop button; when pressed, the circuit is broken. And as long as I hold it down, voltage doesn't flow to the contactor coil. But there's a problem: I need to constantly hold the Start button down. What can we do? Let's use the fourth contactor contact. We'll use this to duplicate the Start button, thereby enabling the contactor to latch automatically. There's a jumper between the red and black buttons; we'll connect another wire to this jumper. It can be connected to either side of the jumper. I connected it here because it was more convenient for me. And on the contactor, between terminal A1 and terminal 13, I'll install a jumper. And the wire coming from the pushbutton post jumper, I connect to terminal 14 of the contactor. Now let's test the circuit. I press Start – the contactor is pulled up, the motor turns. And suddenly the voltage disappears. The contactor has dropped, the motor stops. The voltage returns – BUT! The motor doesn't start spontaneously. And it can only be started by pressing the START button again.