The basic stress of an electrical machine is the nominal operating mode and is described in the international standard IEC 60034-1. This is a tool for estimating the suitability of a component (e.g. motor) for the corresponding application. It would be uneconomical to design every machine for every conceivable load, which is why the nominal operating modes have been defined. This makes it possible to take into account how often the motor has to start with which load.
The nominal operating mode is indicated on the nameplate, where information such as the number of switching cycles per hour and the duty cycle can be found. If this is not the case, the motor is designed for continuous operation at constant load.
The following figure shows the different operating modes. Depending on the operating mode, additional information must be provided such as load duration, duty cycle, number of switching cycles, moment of inertia, acceleration and deceleration time.
Figure 10.2.1 | Rated Operating Modes Standard IEC 60034-1