陶瓷和金属正温度系数电加热器功率衰减特性研究

Study on Power Attenuation Characteristics of Ceramic and Metal Positive Temperature Coefficient Electrical Heaters

为空调中辅助电加热器的设计选型提供更准确的依据,本文对广泛使用的2种电加热器功率衰减特性进行研究。采用名义工况下启停运行5,000次及干烧工况下连续运行15天的两种测试方法,结果表明:两种测试方法获得的两种电加热器的功率衰减特性结果比较吻合,金属PTC的功率衰减率分别为3.13%和2.04%,陶瓷PTC的功率衰减率分别为6.00%和8.11%。2种电加热器的功率衰减均为前期较快、后期较慢。根据功率衰减特性,在设计选型时,对2种电加热器的功率均应留有裕量,金属PTC电加热器应选5%,陶瓷PTC电加热器应选10%。

To provide more accurate basis for the design and selection of auxiliary electric heaters in air conditioners,the power attenuation characteristics of two most widely-used heaters have been studied.Two test methods are to run and to stop 5,000 times under nominal operating conditions and continue running 15 days under dry burning conditions.The results show that,the power attenuation characteristics of two heaters between two test methods are agreed,the attenuation rates of metal PTC（Positive Temperature Coefficient） are 3.13% and 2.04%,and the attenuation rates of ceramic PTC are 6.00% and 8.11%.The power attenuation rates are faster in the earlier stage and slower in the later stage.So,there must be allowance in the design and selection;the power of the metal PTC heater is selected as 5% and that of the ceramic PTC heater is selected as 10%.