《电世界》1995年第6期《消防水泵控制回路设计的改进》一文中,有关消防水泵的控制原理图尚有再改进之处。现将原文中原理图存在的问题(见图1)和再改进意见(见图2)说明如下。 1.图1中,热继电器触点1RJ、2RJ置于接触器线圈1C、2C的中性线一侧不符合AC220V回路的设计原则,即控制电源为AC220V时,其电路中所有控制及保护触点必须设置在被控线圈的相线一侧,否则当置于线圈中性线一侧的控制及保护触点出现接 “Electric World” No. 6 of 1995 “fire pump control circuit design improvements” one article, the fire pump control schematic there are still some improvements. Now the original principle of the problem (see Figure 1) and then improve the views (see Figure 2) are described below. 1. In Figure 1, the thermal relay contacts 1RJ, 2RJ placed on the neutral side of the contactor coils 1C, 2C do not meet the design principle of the AC220V circuit, that is, when the control power supply is AC220V, all the control and protection contacts The point must be set on the phase side of the controlled coil, otherwise the control and protective contact placed on the neutral side of the coil