The brushless motor has a fairly high efficiency - about 93%. He can 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 shutoff valves in the oil and gas industry, since they do not have brush assemblies, which means that there is no sparking. In the automotive industry they are used as engines for windshield wipers, power windows. They are also used in
medical equipment, robotics.
Its essence is that the brushless motor is a direct current machine with an inductor - a rotor and an armature winding made on a stator. The function of the missing brush unit is performed by a semiconductor switch that feeds the armature windings and switches them in accordance with the position of the rotor. The most common option is a brushless motor with a three-phase stator winding.
The rotor can represent various options in design, which depends 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 maximum torque. The stator windings can be powered from any semiconductor converter.
Making homemade brushless motors
These devices are very attractive for aircraft models, as they gain maximum speed in a few seconds. It is they who are trying to make a brushless motor with their own hands at home, since brushless models produced by the industry are very expensive. The body, as a rule, is whetted from duralumin. 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 winding of copper, 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 or more. Switching between the windings is carried out by electronic circuits - inverters. The entire device is assembled in the following order:
- magnets are installed in the correct order;
- a thread is cut on the shaft;
- further holes are drilled to facilitate weight and cooling;
- the stator winding is carried out with copper wire;
- soldered connectors;
- bearings are installed;
- snap rings are installed.
Next, the assembled brushless motor is connected to a power source and its performance is checked. If everything is functioning properly, then you can install it on an airplane model. Thus, a homemade brushless motor is quite possible to create.