机井水泵电动机烧坏的原因：1) 水泵靠电动机旋转才能提水。三根相线正常时，线电压为380V,电流也有一定数 值。当发生下列情况时，电流会增大：①地下水位下降，使水泵扬程超过规定值；②水泵、 电动机有故障；③电网电压偏低，当电流过大时间长了，电动机就发热，直到烧坏线圈， 特别是当三根相线中的一相断线（又叫缺相）时，更容易将电动机烧毁。
The causes of motor burnout of pump in machine well are as follows: 1) The pump can lift water only when the motor rotates. When the three phase lines are normal, the line voltage is 380V, and the current has a certain value. When the following conditions occur, the current will increase: (1) the groundwater level drops, causing the pump head to exceed the prescribed value; (2) the pump and motor are faulty; (3) the voltage of the power grid is on the low side, when the current is too large for a long time, the motor will heat until the coil is burnt out, especially when one of the three phase lines is broken (also known as the phase gap). It's easier to burn the motor down.
2) 灌溉季节，往往电力紧张，供不应求，电压明显偏低，有时农村用电电压只有300V 左右，若这时高压线中断了一相，两相供电，若不及时拉闸，引起该线路电动机同时烧坏。
2) In irrigation season, the power supply is often tight, the supply exceeds the demand, and the voltage is obviously low. Sometimes the rural power supply voltage is only about 300V. If the high-voltage line interrupts one phase and two-phase power supply, if the switch is not pulled in time, the line motor will burn out at the same time.
3) 有人缺乏安全保护知识或图省事，将刀开关上的熔丝换成大号的，或干脆换成 铜线，有的则用绳子把磁力开关绑住，强制不让跳闸。
3) Some people lack the knowledge of safety protection or try to save time by replacing the fuse on the knife switch with large size, or simply replacing it with copper wire. Others use ropes to tie the magnetic switch and force it not to trip.
4) 电动机已经严重发热，还是连续不停地使用。
4) The motor has been seriously heated or continuously used