The present invention relates to set free pump protector liquid air defense, which is characterized in that the self reference memory protection module is a numerical automatic memory working current for reference as the no-load current setting value starting after the normal operation of pump motor, when there is no liquid idling the working current drops below the no-load current automatic memory setting when the value of protection automatic shutdown, can greatly reduce the product specifications, each specification can be arbitrarily used in a large range, solve the set out of calibration or other reasons caused by error protected or not the phenomenon.
【技术实现步骤摘要】
【技术保护点】
1.无设定泵类无液防空转保护器,包括无设定泵类无液防空转自定基准记忆保护模块或三相无设定泵类无液防空转保护器或单相无设定泵类无液防空转保护器,其特征在于无设定泵类无液防空转自定基准记忆保护模块是泵类电动机起动结束后正常运行时开始自动记忆以工作电流的90%左右为基准作为空载电流设定值,当出现无液空转使工作电流下降到低于自动记忆的空载电流设定值时起保护作用自动停机,具体是泵电动机的工作电流信号Iex经电阻R26连接电位器W1和电阻R27分压,电阻R27的另一端接公共端,电位器W1滑动端连接电阻R28,电阻R28另一端连接电解电容器C11正极和电阻R29,电解电容器C11负极连接公共端,电阻R29另一端连接运算放大器U1D负输入端和二极管D15正极,电位器W1滑动端信号为小于工作电流90%可调,通过电阻R28给电解电容器C11充电,在电解电容器C11上获得基准信号连接运算放大器U1D负输入端,运算放大器U1D正输入端连接电阻R25,电阻R25另一端连接工作电流信号Iex和电阻R26,当工作电流信号Iex低于基准信号时运算放大器U1D输出端反转通过二极管D17控制停机,运算放大器U1C正输入端 ...
【技术特征摘要】
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