Elements of Thermal Calculus of Components in Electromechanical Brushless Converter With Open-pole Stator and External Rotor With Permanent Magnets

Brushless motor with open-pole stator and permanent magnet rotor characterized by sufficient simplicity of design and manufacturing techniques. It is also relatively economical for asynchronous electric machines. At the same time, it provides much higher quality consumer characteristics. According to the widespread use of traditional designs with internal rotor gearless drive for a number of mechanisms is often necessary to use a design with external rotor. This design is simple, reliable, technological and economical. Methods of synthesis, optimization and research brushless motor with external rotor and permanent magnets require a simple and reliable method of the thermal state calculation of the main components, as it affects energy performance and reliability of this machine.
Estimation features of a thermal condition of the main components of the brushless electromechanical converter with an open-pole stator and an external rotor with permanent magnets are considered in the article. Particular attention is paid to the importance of such an assessment for electromechanical brushless converters with permanent magnets on the rotor, the maximum allowable operating temperature for which is limited to low values. Such magnetic materials are known to be significantly cheaper at high-energy values, but lose, often irreversibly, the magnetic properties when the temperature of the allowable heating is exceeded. On the other hand, for a number of applications of such an electromechanical converters. For example, in motor-wheel in vehicles, the cooling surface of the rotor with permanent magnets is closed-type, which gives grounds to consider the need to assess the thermal state of the main components of the electromechanical converter of brushless motor, especially external rotor with permanent magnets, in all stages of its design — synthesis, optimization of geometric dimensions and research.
The proposed method of a thermal calculus of brushless electromechanical converter elements, such with permanent magnets on the rotor, allows with sufficient accuracy for engineering practice to perform appropriate calculations of these motors, in particular, for direct drive of mechanisms.