The brushless motor has a fairly high efficiency - about 93%. It can also develop more power. Its main advantage is the absence of a brush assembly, which immediately increases reliability.
In this case, the service life of the device depends only on the service life of its bearings. It is much less noisy compared to collector motors. Due to their properties, they have found wide application. For example, they are part of shut-off valves in the oil and gas industry, since they do not have brush assemblies, which means there is no sparking. In the automotive industry, they are used as motors for windshield wipers, power windows. They are also used in medical equipment, robotics.
Its essence lies in the fact that a brushless motor is a DC machine with an inductor-rotor and an armature winding made on the stator. The function of the missing brush assembly is performed by a semiconductor switch, which feeds the armature windings and switches them in accordance with the position of the rotor. The most common option is a three-phase brushless motor.stator winding.
The rotor can present various design options, depending on the location of the magnets on it. As a result of the interaction of two magnetic fluxes, a torque arises from the stator and rotor. With the help of rotor position sensors, the angle between the two streams will always be maintained in the range of 90°, which will create the maximum torque. The stator windings can be powered from any semiconductor converter.
Making homemade brushless motors
These devices are very attractive to aircraft modellers, as they gain maximum speed within a few seconds. It is they who are trying to make a brushless motor with their own hands at home, since the brushless models produced by the industry are very expensive. The case, as a rule, is sharpened from duralumin. The magnets come from old CD drives.
The rotor of such motors has from two to eight pairs of poles. The stator consists of a housing, as well as a core, which is made of electrical steel and a copper winding, which fits into special grooves around the perimeter of the core. The number of windings corresponds to the number of motor phases, and they can be single-phase, two-, three-phase and more. Switching between the windings is carried out by electronic circuits - inverters. The assembly of the entire device is carried out in the following order:
- magnets are installed in the correct order;
- thread is cut on the shaft;
- nextholes are drilled for light weight and cooling;
- the stator is wound with copper wire;
- solder connectors;
- bearings are installed;
- retaining rings are installed.
Next, the assembled brushless motor is connected to a power source and its performance is checked. If everything is functioning normally, then you can install it on the aircraft model. Thus, a homemade brushless motor is quite possible to create.
