Asynchronous motors differ from each other in the number of phases, supply voltage, and rotor design. The choice of such a motor is determined by the operating conditions, as well as the parameters of the supply circuits.
Instructions
Step 1
It is difficult to purchase asynchronous electric motors with supply voltages below 127 V. In addition, all such motors are capable of operating only on alternating current. If the mechanism that is supposed to be set in motion contains only low-voltage circuits, or direct current circuits, an inverter will have to be used. It is quite expensive and takes up a lot of space, so consider using a brushed or brushless motor instead of an asynchronous motor. The use of an inverter is justified only when it is necessary to combine a long service life of the motor with the possibility of smooth adjustment of the speed.
Step 2
If there is only single-phase AC voltage and there is no need for reversing, opt for a single-phase asynchronous motor. It has only two pins and does not require additional components to operate. It is impossible to change the direction of its rotation, and the efficiency is slightly less than that of other asynchronous motors. They are usually rated for 220 V, but there are exceptions.
Step 3
If you need to reverse the motor, but the network is still single-phase, use a two-phase motor. Operation from a single-phase network is normal for it, and one capacitor is required from additional components. Its parameters and connection diagram are indicated in the documentation for the motor, and sometimes directly on it. Please note that many of these electric motors are rated at 127 V, and therefore can only be operated from a 220-volt network through an autotransformer. Do not try to use a three-phase instead of a two-phase motor in a capacitor circuit, especially with a large mechanical load. It is not designed for this, and the consequence of such experiments can be a fire.
Step 4
In the presence of a three-phase network, it is most rational to use a three-phase motor. Like two-phase, they are reversible, but do not require additional components (except for protective devices), like single-phase. On each of them, two voltages are indicated through a fraction: the smaller one is for turning on with a triangle, and the larger one is for turning on with a star. The most common motors are 127/220 and 220/380 V. Select the switching circuit depending on the voltage of the three-phase network.
Step 5
Some asynchronous motors of the above types are available in squirrel-cage design. Instead of a shaft, they are equipped with rotating outer cylinders. In some cases, it is more convenient to pair such motors with the mechanisms they set in motion.
