With every right to say that electric motors are the basis of modern civilization. With the current level of progress, they represent one of the most efficient solutions for converting one form of energy into another.
Electric motors are so widespread that sometimes, looking at a particular device, it is impossible to even assume that it uses any kind of electric motor. For example, few people know that in some mobile phones the vibration mode is implemented due to the rotation of the shaft of a compact motor with an eccentric mounted on it. Not surprisingly, even fewer people know how to connect an electric motor. Although, frankly, there is nothing complicated about it. To understand how the electric motor is connected, there is no need to complete electrical engineering courses or delve into the peculiarities of the interaction of magnetic fields inside the device case.
Roll upsleeves…
Connecting an electric motor does not begin at all with applying voltage to the terminals, but with an inspection of the device specification. Any electric motor (unless, of course, it has been in the hands of vandals and has not been operated in an aggressive environment) always has a small plate that indicates the type, efficiency, voltage and current, nominal shaft speed, etc.
If you ignore this data and connect the electric motor, then it is quite possible to damage the power supply, conductors or the motor itself.
One of the key points is power (in kilowatts). Its value affects the cross section of the wire core, which will be supplied with voltage. The dependence of the conductor cross section on current and power is given in a special table (can be found in the PUE).
AC Solutions
Since asynchronous motors are more widespread, we will consider them further. Opening the born cover (terminal box), you can see a dielectric block with a number of leads. Motors designed for three-phase networks can have 3 or 6 contacts. In the first case, the connection is simple: a phase (380 V) is connected to each output, and if necessary, change the rotation, any two of them need to be swapped.
6-pin motor circuit is more flexible. Usually on the plate in the “Voltage” column two values \u200b\u200bare indicated at once: 220 and 380 Volts (or 380 and 660). This means that, depending on the method of power supply, the potential forwindings will be different. There are two versions of them: "triangle" and "star". There are three windings inside the motor, the beginnings and ends of which, respectively, are designated C1-c4, C2-c5, C3-c6. The plate always indicates the correspondence of the connection to the voltage, that is, 220/380 with "triangle / star" means that the connection scheme of the internal windings, for example, in a star, is used for a 380 V network. This should not be confused, unless, of course, you want carry out unscheduled repairs to the electric motor.
Connecting pins
Assume that the desired voltage is selected. According to the plate, we determine the connection scheme. It remains to correctly install the jumpers between the terminals and apply voltage. For a star, bridges should be installed between contacts C4-C5-C6, and opposite phases should be connected to C1, C2 and C3. For a triangle, the scheme is different: jumpers are placed between C3-C5, C2-C4 and C1-C6. In a two-wire network, the third "phase" can be obtained by turning on an auxiliary capacitor. This scheme is widely available and therefore not covered here.
Each of the ways to connect the internal windings has its own characteristics: one has large currents and power, and the other has smooth operation. The correct scheme should be selected based on the network capabilities and the tasks solved by the electric drive.
