Impact detection of intelligent AC contactors and optimization of the dynamic characteristics

The closing process of intelligent AC contactors can be affected by selection phase angle. A control strategy is proposed to compensate the influence of closing process at different phase angles. In order to evaluate the dynamic characteristics of the contactor, an impact detection sensor is developed to measure the impact in the rigid body collisions by using PVDF. The PVDF sensor is used to measure the impact between the armature and the static core of an electric contactor. The stress sensitivity of PVDF is calibrated with a commercial impact force sensor. Experimental results show that the duration of the rigid body collision is around 0.5 ms and the magnitude is about 700 N. Larger current comes with larger impact. By using the proposed control strategy, the impact force can be decreased and the consistency of the dynamic closing process can be guaranteed.