motor controlling board and auto controlling board with neutral line replacement and method thereof

PURPOSE: A motor control board/automatic control board and a neutral line replacement method are provided to prevent the operating failure of a connecting load by immediately and accurately detecting and alarming short circuit of a neutral line. CONSTITUTION: A phase open relay(210) detects phase open of power supplied. A controller(220) generates a control signal for replacement of a neutral line. A neutral line protector(230) replaces a neutral line for maintaining balanced single-phase voltage. An alarm generator(240) makes an alarm informing short circuit of a neutral line according to an alarm generation control signal output from the controller. An alarm release signal input part(250) generates an alarm release signal and transmits the alarm release signal to the controller.