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A Control and Command System (SECAM-4/5A) designed for the Plasma Focus Installation IPF-4/5A (1 MA plasma current and 40 kJ energy stored at 20 kV charging voltage) is presented.

A single shot pulsed power source was developed using two helical flux-compression generators. At an initial 5 kA current injected in the system, a Rogowski coil located in a 4 nH final inductive load recorded a peak current of more than 11 MA. For our application, the pure inductive load will be replaced by a metal foil fuse having the same inductance. The obtained conditions are sufficient to deliver, through a dielectric breakdown switch, a current of more than 2 MA with 4 /spl mu/s risetime on a plasma focus load.

The paper presents some results obtained by the authors in the manufacture and use of equipment and adjacent measuring and diagnosis devices developed for the research of electrical switching arcs in vacuum. Tests were made for the current range 0.5-30 kA RMS and voltages between 200-1400 V. The evolution of currents and electrical switching voltages related to mechanical and vacuum breaking process parameters was recorded. Diagnosis measurements relatively to the diffuse or constricted state of the breaking electrical arc column were also performed. Research concerning the influence of the additional magnetic field upon the electrical switching arc in a vacuum have also been initiated.

The paper presents one stage of the scientific research, performed for the investigation of the post-arc (p.a.) current within low voltage switching process in vacuum, when interrupting short-circuit currents of high values. A large power equipment, supplied by the mains and providing an accurate reproduction of the processes, concerning the short circuit phenomenon (U=1.5 kV; I=100 kA) was used. An experimental model, which can reproduce the switching conditions of the power circuit-breaker in vacuum, was available as well. The influence of an axial magnetic field on the p.a. current and the switching process was also explored.

The paper presents an investigation of the post-arc current within low voltage switching process in vacuum. From the experimental results were deduced the constants fitted for the adopted simplified mathematical one-dimensional post-arc model. By comparison between the experimental and calculated evolution of the post-arc current and transient recovery voltage, in the first /spl mu/s after the current zero moment, one can obtain an efficient tool for predicting the vacuum circuit breaker behavior, or for improving it.

The plasma-focus device (PFD) discharge chamber consists essentially of two coaxial electrodes and an insulator across which the initial breakdown occurs. The central electrode attaches to a central header that provides an electrical connection to the PFD driver (pulser). The main goal is to achieve very high average EM power delivered to the PFD. The only method to reach the desired average output power is magnetic pulse compression (MPC). A 200 J/pulse, 50/100 Hz magnetic pulse compression circuit (MPCC) has been designed. The circuit has a 25 kV working voltage, and compresses a 29.5 /spl mu/s/1 kA pulse into a 560 ns/100 kA plasma current pulse. The PSPICE simulation of this MPCC is discussed.