设置
快速交货
免运费
国际贸易术语
支付类型
市场产品
The lifetime of an aluminum electrolytic capacitor is a very important feature. Aluminum electrolytic capacitors slowly degrade over time and once the capacitor has degraded beyond a specified amount, the capacitor is considered to have failed. The temperature has the largest effect on life, the relationship between life and temperature is defined by the Arrhenius law. This law states that the life of an aluminum electrolytic capacitor doubles for every 10°C decrease in temperature. Another way to increase life is to derate the voltage. If Electrolytic capacitors are operated at a voltage below their rated value then the component will be under less operating stress which improves life. The graph on the left shows the relationship between derating factor and the percentage of rated voltage. The recommended derating percentage is 85% for maximum benefit. Life expectancy at full rated voltage is multiplied by the voltage derating factor which is provided by KEMET to calculate the new life expectancy. This short example on the right will help clarify derating. This part number shown has a rated voltage of 400 with 105°C and 7000 hours life. Using the recommended derating percent, derate the part for 15%, 15% of 400 is 60 and subtract 60 from 400 to get 340 V at 105°C the Kv is 1.35. Using the formula above multiply life expectancy at rated voltage (7000) and multiply it with derating factor (1.35) get 9,500 hours. That is 2,500 extra hours gained just by derating the voltage.
