The relevance of energy efficiency is not only promoted from high stands, but is already a key characteristic in the creation of new modern products and complex systems corresponding to the sixth technological paradigm. Since, according to world statistics, about half of all generated electricity is consumed specifically for powering electric motors, the value of their efficiency (efficiency) is of particular importance. And when it comes to the household level about quadrocopters or electric cars, everyone wants them to fly and drive as long as possible without recharging.
Mnom – rated torque (in S1 mode), N * m; Mmax – maximum torque (in S2 mode), N * m; Pnom – rated power (in S1 mode), kW; Pmax – maximum power (in S2 mode), kW; N – rated speed, rpm
In a nutshell, the efficiency of an electrical machine (electric motor or generator) can be defined as the ratio of mechanical power to the supplied electrical power.
It is known that with a decrease in speed, the mechanical power of the electric motor decreases linearly, and the power of electrical losses while maintaining the nominal torque remains almost constant. This leads to the fact that the efficiency steadily decreases with decreasing revolutions, and at zero revolutions formally becomes equal to zero.
In general, the efficiency of an electric motor depends not only on the speed, but also on the magnitude of the torque. If in the operating range of revolutions it is not required to maintain the maximum or nominal torque, then the numerical indicator of efficiency can be slightly improved by reducing electrical losses.
All motor manufacturers now strive to achieve the maximum efficiency of their electric motor, preferably over 90%. However, not everyone succeeds: for such widespread low-power asynchronous and stepper motors this is basically impossible, and for synchronous motors, much depends on the way of solving the problem of pole “sticking” and parasitic electrical losses in the stator.
Special versions of EM motors with the ultimate and record-breaking specific performance in their class
If you twist a synchronous electric machine by the shaft, then in most cases you will feel magnetic “sticking”, in which the shaft will rotate in jerks. This effect is associated with the presence of permanent magnets in the rotor and strongly depends on the design of the multi-pole “stator-rotor” system of the electrical machine. Some synchronous electric motors cannot even be turned by hand, so there is a strong pole “sticking”. During operation, such electric motors emit increased noise or rattling, which are louder, the more pronounced the “sticking” effect is.
But for synchronous electric motors of the EM and iEM series, pole sticking is practically absent (less than 1 N * m)! This is achieved thanks to the patented stator and rotor layout.
No pole sticking and record efficiency thanks to patented CCSC-3 composite stator technology
As a result, for the rotation of these electric motors it is not necessary to spend additional energy to overcome the “sticking”, which allows to achieve a higher efficiency. In the electric motors of the iEM series, which have an iron core, the efficiency can reach 95%, and in the electric machines of the AW and EM series, which do not have an iron core in the stator, the efficiency can reach a record 98.5%!
To qualitatively measure the efficiency of an electric machine in the entire operating range of revolutions and torques, a special measuring stand is required, which is available only to manufacturers of electric motors and electric drives, and even then not to all. Realizing their impunity, most innovators do not hesitate to publish high efficiency rates of their synchronous electric motors, despite the monstrous “sticking” of the rotor of their designs. For example, if the nominal torque of a synchronous motor is 100 N * m, and the pole “sticking” moment is 10 N * m, then the efficiency of the electric motor will not be able to reach the bar of 90% or more without violating the law of conservation of energy. However, the inventors of Perpetuum Mobile will never run out.
