Abstract: This paper applies the qualitative analysis and experimental verification to the torque hopping problem of EAS013/014 VB electric equipment of Nuclear Power Plant by applying the root cause analysis method.Valve start,the inertia is too large to make the remote transmission speed of 120 r/min caused by the motor worm move in short time,so that the torque switch protection,the performance of torque jitter.Through the analysis of the principle of the electric device and field experiments,it is concluded that improper selection of the electric device,which leads to the torque jump of the electric device,has important reference significance for the selection of the electric device with the remote control operation.