Specific weight-dimension factors of the electric drives

The Specific weight-dimension factors of the different types of electric drives and the ways to improve them are considered. To compare the specific parameters of synchronous motors with permanent magnets the minimum total losses criterion, previously proposed by Professor Vagati, was chosen. The convenience of this method is that it allows you, without resorting to complicated electromagnetic calculations to choose the optimum value of the rated speed. To compare the specific parameters of the classical asynchronous drives the electromagnetic torque expression, proposed by Professor Kopylov for classical electrical machines, was selected. The equation, which shows the relations between the electromagnetic torque and the geometric parameters of the motor, allows identifying «weak» links in the induction motor and explain its limit values. The author shows the ability of creation the torque in the field regulated reluctance machine by the higher harmonic of the current. It is shown that designing electrical machines with considering the peculiarities of the semiconductor inverter and motor cooperation it is possible to improve the specific indicators up to 30%. The paper notes that applying new approaches can increase the overload capacity of the drive, and hence its use at sites with heavy and extraheavy operating conditions