An asynchronous machine is a device that runs on electricity with alternating current, and the speed of the machine is not equal to the speed of the magnetic field that is generated by the current in the stator winding. So what types of such devices are there and how do they work?
Instructions
Step 1
In some countries, collector machines are also referred to as such devices and are also called asynchronous induction machines, which is explained by the process during which the current in the rotor winding is induced by the stator field. The modern world has found application for asynchronous machines as electric motors, which are converters of electricity energy into mechanical force.
Step 2
The great demand for such devices is explained by their two advantages - easy and fairly simple manufacture and the absence of contact of electricity in the rotor with the stationary part of the machine. But asynchronous machines also have their disadvantages - they are a relatively small starting torque and a significant starting current.
Step 3
The history of the creation of asynchronous devices goes back to the Englishman Galileo Ferraris and Nikola Tesla. The first in 1888 published his own research, which laid out the theoretical foundations of such an engine. But Ferrares was wrong in thinking that an asynchronous machine has little efficiency. In the same year, the article by Galileo Ferraris was read by the Russian Mikhail Osipovich Dolivo-Dobrovolsky, who already in 1889 received a patent for a three-phase induction motor, arranged like a squirrel-cage rotor "squirrel wheel". It is this trinity that pioneered the era of the massive use of machines on electricity in industry, and now asynchronous devices are the most common motors.
Step 4
The principle of operation of asynchronous devices consists in supplying alternating voltage through the windings with current and with the further creation of a rotating magnetic field. The latter, in turn, affects the rotor winding, in accordance with the law of electromechanical induction, and interacts with the stator field, which rotates. The result of these actions is the impact on each tooth of the rotor magnetic circuit of a force that folds exclusively around the circumference and creates a rotating electromagnetic moment. It is these processes that make the rotor rotate.
Step 5
Modern and used asynchronous motors are divided according to control methods into the following types - rheostat, frequency, with switching of windings according to the "star" scheme, pulse, with a change in the number of pole pairs, with a change in the amplitude of the supply voltage, phase, amplitude-phase, with inclusion in the circuit feeding the stator of the reactor, as well as with an inductive type resistance.
