When several electrical components in a device are combined into an input module, the individual power losses and temperature deviations of all components involved must be carefully taken into account to ensure safe long-term operation.
Power supply modules (PEMs) consist of a combination of different components for the safe power supply of devices. In addition to the IEC input connector for devices, mains switches, fuse holders or circuit breakers and filters can be integrated. All these components are tested according to their respective component standard so that the entire component can be certified by the certification authorities.
Each of these components is designed for a specific minimum and maximum ambient temperature. Important: The maximum rated current should only be used at the rated temperature. At higher ambient temperatures the current must be reduced accordingly. This is usually specified in the temperature deviation on the datasheets.