| | | HOT SPOT (THERMAL) CALCULATION You can calculate the maximum operating (hot spot) temperature of this capacitor in the following manner: Polypropylene has a constant loss factor (tgSo) of 2x10-4 irrespective of temperature and frequency (up to 1 MHz). The loss factor of the capacitor is made up of the sum of two components. The first represents electrical losses (tgS0 = 2.10-4) and the second represents Joule effect in the connection and foils: Rs.C.2nF. For all applications, the temperature in the hot spot capacitor must be lower than 85°C. | | Heating calculation of hot spot capacitor: FAI1 FAI2 FAI3 9 hot spot = 9 terminals + (tg80-Q + Rs-(Irms)2)-Rth Heating calculation of hot spot capacitor: FAI6 9 hot spot = 9 water + (tg80Q + Rs-(Irms)2)-Rth With: tg50 = 2.10-4 Q in Var Rs in Ohms Irms in Amperes Rth in °C/W (water flow = 10 dm3/minute) Note: The life time depends of hot spot temperature, see following curve. | | |