Brushless motor - advantages and applications

The brushless motor has a rather high efficiency - about 93%. He can develop more power. Its main advantage is the absence of a brush assembly, which immediately improves reliability. In this case, the life of the device depends only on the life of its bearings. It is much less noisy compared to the 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, so there is no sparking. In the automotive industry, they are used as engines for windscreen wipers, window lifters. They are also used in medical equipment, robotics.

The essence of it is that the brushless motor is a DC machine with an inductor - a rotor and an armature winding made on the stator. The function of the missing brush assembly is performed by the semiconductor switch, which supplies 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 a variety of designs, depending on the location of the magnets on it. As a result of the interaction of the two magnetic fluxes, a torque arises from the stator and the rotor. With the help of rotor position sensors, the angle between two flows 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.

Manufacture of self-made brushless motors

These devices are very attractive for airplane modelers, since within a few seconds they gain the maximum speed. They are trying to make a brushless motor with their own hands at home, as the commercially available brushless models are very expensive. The body, as a rule, is ground from duralumin. Magnets are taken from old CD-drives.

The rotor of such engines has two to eight pairs of poles. The stator consists of a body, and also of a core, which is made of electrical steel and a copper winding, which fits into special grooves along the perimeter of the core. The number of windings corresponds to the number of phases of the motor, and they can be single-phase, two-, three-phase or more. Switching between windings is carried out by electronic circuits - inverters. The whole device is assembled in the following order:

- magnets are installed in the right order;

- the thread is cut on the shaft;

- further holes are drilled to facilitate weight and cooling;

- the stator winding with copper wire is performed;

- Solder the connectors;

- bearings are installed;

- Snap rings are installed.

Further, the assembled brushless motor is connected to the power source and its operability is checked. If everything is working properly, then you can install it on the airplane model. Thus, a self-made brushless motor is quite possible to create.