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我矿一台磨粉机控制柜,安装后运行了两年多,没有出现过故障。前不久却发生了一起二次线路中主要电气设备烧毁的事故。事故发生后经过仔细检查,才弄清楚是错误地将地线当零线(工作零线)接线造成的。事故分析如下。如附图所示,我矿生产车间由两台变压器供电。一台为SJ-240/10,另一台为SJ-75/10型,两台都是Y/Y_0—12连接组。两台变压器的保护零线接在同一地线网上。正常时U_(aa′)=U_(bb′)=U_(cc′)=0VU_(ab′)=U_(ac′)=U_(bc′)=U_(ca′)=U_(cb′)=380 V图中,R_L为磨粉机控制柜二次线负载电阻。R_1的正常工作电压(额定电压)为220 V。安装磨粉机控
I mined a mill control cabinet, run more than two years after installation, there have been no failures. Not long ago there was an accident involving the destruction of major electrical equipment in the secondary circuit. After careful examination of the accident occurred, it was clear that the wrong ground will be zero line (work zero line) caused by wiring. Accident analysis is as follows. As shown in the photo, my mine production workshop is powered by two transformers. One for SJ-240/10 and the other for SJ-75/10, both of which are Y / Y_0-12 connection groups. Two transformer protection zero line connected to the same ground network. Normal U_aa = U_bb = U_c’ = 0 VU_ ab ’= U_ ac’ = U_bc ’= U ca’ = U_cb’ = 380 V In the drawing, R_L is the secondary line load resistance of the mill control cabinet. R_1’s normal operating voltage (rated voltage) is 220 V. Install milling machine control