电气故障产生的主要原因是：
The main causes of electrical faults are:
电气故障包括：内部故障和外部故障。
Electrical failures include internal and external failures.
电气设备的有些故障是由于设备内部因素造成的，如电磁力、电弧、发热等，使电气设备结构损坏、绝缘材料的绝缘击穿等。这类故障称为设备内部故障。
Some faults in electrical equipment are caused by the internal factors of the equipment, such as electromagnetic force, arc, heat and so on, which make the structure of the electrical equipment damaged, insulation breakdown and so on. This kind of fault is called the internal fault of the equipment.
电气设备的另一些故障则是由外部因素引起的，如电源电压、频率、三相不平衡，外力及环境条件等，使电气设备形成故障。这类故障称为设备外部故障。
Other faults in electrical equipment are caused by external factors, such as power supply voltage, frequency, unbalanced three-phase, external force and environmental conditions, so as to make electrical equipment malfunction. This kind of fault is called the external fault of the equipment.