Development of an application specific integrated circuit for reduction of contact bounce in three phase contactors

In this paper, a miniature control device capable of reducing contact bounce in three phase contactors is presented. The device is implemented using Alcatel-Mietec 2 /spl mu/m integrated circuit technology and operates by controlling the strength of the kinetic energy of the field flux by timing the coil energisation periods. The device performance is evaluated through a series of tests with line-to-line voltages of 75 and 300 V and a gap length of 2 mm. Results demonstrate that, with the appropriate input settings to the control device, it is possible to eliminate contact bounce substantially in all three phases. The mechanical characteristics of the contactor system determine the required setting for zero bounce. The ability to vary the input data results in a device which can be tailored to application with any type of switchgear. On completion of 5000 switching operations using the control device, the active area of erosion on each of the contact surfaces is reduced by a factor of up to 28% compared with contacts from tests where no control device is used. Furthermore, comparisons with previous studies indicate that the majority of the erosion that occurs with controlled switching is caused by arcing during the opening operation. Hence, it can be concluded that the frequency and duration of the arcs which occur during closing are substantially reduced by the use of the control device.