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1 直联真空泵的负载特点按照国际标准,油浸式直联真空泵不但应达到各项规定的真空指标,而且真空泵最低启动温度应不高于10℃,在环境温度5-40℃和相对湿度不大于90%的条件下应能正常工作。在如此低的温度下(10℃)真空泵油一般比较粘滞,甚至呈胶状,致使冷态的油浸式电机定转子之间(0.1-0.2mm)的气隙被填充粘连成为一个惯性极大的弹性刚体。这时如果电机以直接方式起动,则在冷态的首次启动处于堵转状态,启动电流异常大,并且过渡过程时间较长;然而进入热稳态时真空泵又是一个低功率因素负载,COSφ往往低于0.2-0.45,需要过流保护值又低,
1 Direct-coupled vacuum pump load characteristics According to international standards, oil-immersed direct-coupled vacuum pump should not only meet the requirements of the vacuum indicators, and the minimum starting temperature of the vacuum pump should not exceed 10 ℃, the ambient temperature 5-40 ℃ and relative humidity is not More than 90% of the conditions should be able to work properly. At such a low temperature (10 ° C) vacuum pump oil generally more viscous, or even in the gel, so that the cold state of the oil-immersed motor between the stator (0.1-0.2mm) air gap is filled into an inertia pole Big flexible rigid body. In this case, if the motor is started in direct mode, the first start-up in cold state is in a blocked state, the starting current is abnormally large, and the transition process takes a long time; however, the vacuum pump is also a low-power load when entering the steady- Below 0.2-0.45, over-current protection is required and low,