Design And Experimental Study Of Pulsed Current Impacting Equipment

Pulsed power technology, which researches the generation and transmission of high pulsed voltage, current and power, has widely development and application prospects, as one of the basic disciplines of contemporary high technology. High voltage switch is an important part of pulsed power system, and its performances directly influence output parameters and stability of the equipment. The high voltage switch, which is the key to the success of pulsed power system, must run in the conditions of high operating voltage, current and repetition rate, low jitter and short breakdown time.In this paper, pulsed current impact equipment was designed, which consists of voltage regulator, high voltage transformer, rectifier bridge, current limiting resistor, pulsed capacitors, high voltage switch and load. A three-electrode gas-spark switch was designed for high-voltage power supply system. The switch was electrically tested with an experimental circuit to detect the influence of gas pressure and electrodes distance on the working voltage and delay time of switch. The triggering system uses independent power systems, controlling by pulsed transformer or thyristor. The equipment designed can output10kV of voltage,100kA of current,10kJ of stored energy.Material surface modification experiment was done by HOPE-I type high current pulsed electron beam. Output electrical parameters of the equipment were set:capacitance is1μF, voltage is27kV. The surface of Specimen is brightness with uniformity energy after being treated. The beam spot is standard in size, and the diameter is φ30mm.The electromagnetic impact welding and electromagnetic thermal crack prevention experiments were done in the pulsed current impacting equipment designed, based on the electrical parameters and load by structural designing:1. Electromagnetic impact welding is mainly generated by magnetic effect of pulsed current impact on metal. Output electrical parameters of the equipment were set:capacitance is200μF, voltage is9kV. The ringing frequency of current measured is9kHz and the peak of current is100kA. When current flowing through the coil, the impacting force is induced on work-piece, due to the magnetic effect of pulsed current. The work-pieces moves toward each other. The surface of work-piece, behind of coil, has obvious indentation and even is melted. 2. Electromagnetic crack prevention mainly uses thermal effects of pulsed current. Output electrical parameters of the equipment were set:capacitance is100μF, voltage is8kV. The ringing frequency of current measured is16.7kHz and the peak of current is60kA. When current flowing through the work-piece, cracks led to the current flow and concentration effects. The heating is enhancing around the crack tip. The material is melted and solidified with sparks, and the crack is arrested.