The engineer consults the derating chart and discovers that above 30°C, the PSU loses 2 Watts of capacity for every degree of temperature increase.
Airflow: A chart might show two curves—one for "natural convection" (still air) and one for "forced air" (using a fan). Forced air allows for a much higher load at the same temperature. derating chart
Power SuppliesPower supplies are notorious for generating heat. A 500W power supply might be able to provide the full 500W at 25°C, but if the cabinet temperature hits 50°C, the derating chart might reveal it can only safely provide 350W. The engineer consults the derating chart and discovers
Heat is the enemy of efficiency and longevity. When electricity flows through a conductor or a semiconductor, it generates heat (Joule heating). If the surrounding air is already hot, the component cannot dissipate its internal heat effectively. When electricity flows through a conductor or a
| Number of Current-Carrying Conductors | Percent of Ampacity | |----------------------------------------|---------------------| | 1-3 | 100% | | 4-6 | 80% | | 7-9 | 70% | | 10-20 | 50% | | 21-30 | 45% | | 31-40 | 40% |