There is an electrical preventive maintenance task assigned to the Ground Fault Circuit Interrupter, that requires periodic testing of the unit.
应指定接地故障断路器的电气预防维护任务，此项任务要求对装置进行定期测试。
2
The fault characteristic periodic signals of the rolling bearing are in low frequency band and often buried in the noise.
反映滚动轴承故障的特征周期信号处于较低频带内，容易被噪声淹没，难以检测。
3
A new approach to extract weak periodic signal from strong noise is proposed to pick up some weak signals in the fault diagnosis of mechanical equipment.