Mike Krzyzewski is really a famous coach of Dream Team. She has coached north america men's basketball team for some time, that's clinched numerous medals for his country. Following Londonfl jerseys supplyn Olympic was over, Krzyzewski told The Associated Press that this game will be his final one as national coach, a job he's held for seven years. He had left open the possibility of swomen nfl jerseystaying with the team beyond the London Games, when practice on Saturday said these will be his last Olympics.When asked if he was sure, Krzyzewski didn't hesitate before again saying, "yecheap nfl jerseys wholesales," this will be his last game "If we could win it, then it might be three major championships in a row, i always do not know when that has been done because we haven't usually won http://govoriotkrito.bg/libs/nflcn08.htmthe globe championships," Krzyzewski said. "It becomes an enormous thing for the program." Whatever, he's an awesome coach. His achievement are going to be remembered by the country.cheap nfl jerseys
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电磁继电器的负载能力要怎么选择呢

2016/7/28 10:41:51点击:
松川继电器虽然降额设计是电子元器件提高可靠性最有效的措施,但是继电器却不同,不是触点所加的负荷应力越小越可靠。尤其是在高温下,如果电流达到100mA时,触点的电弧不能烧掉其在高温条件下析出的含碳物质,而这些含碳物质沉积在触点表面,使触点接触电阻增大;当触点负荷使用在10mA以下或50mV以下时,由于电压过低无法击穿触点表面的膜电阻,将会出现低电平失效。故电磁继电器的负载能力按如下方法选择:
(1)不同电磁继电器具有不同的负载曲线即负载电压和负载电流的关系曲线

减小负载电压可使负载电流提高,减小负载电流可使负载电压提高,但不存在两者之一无限减小、另一个无限增大的关系,而是两者均有一个上限值。因此在选用电磁继电器负载时,应限制在负载曲线的下方。


(2)电磁继电器的额定负载是指在规定的动作次数(寿命)内,在规定动作频率下,触点所能切换的负载,其种类有阻性负载、容性负载、直流感性负载、电机负载、灯负载、低电平负载等,不同的负载之间各生产厂家有相应的换算关系,如航天3412厂对触点切换不同性质负载大体的电流比例如表1,因此应根据电路中要求切换的负载形式来选择相应的电磁继电器。