Generation of Electrostatically Induced Voltage When Charged Body Moves Away from Ungrounded Metal Box of Different Volume (Depth)

Abstract

Static electricity is used for industrial application of copiers etc. However, such applications could experience an electrostatic accident such as a malfunction or failure of the electronic device. For example, when a charged object, such as a charged human body, exists near a metal housing case, such as an electronic device, an electrostatically induced voltage is generated in the metal case. In general, a malfunction or failure of electronic parts is occasionally caused by a voltage of less than 10V. On the one hand, the voltage of a walking human body in an office with an air conditioner could occasionally exceed 10kV. Very often, an office premises comprises several ungrounded metal housing cases with different volumes (depths). In this study, the relationship between the induced voltages and volume (depth) of a metal case was experimentally determined when a charged object moved away from the metal cases of different volumes. The result shows that the induced voltage in the metal case is 1.4 times higher than the induced voltage on the metal case. The induced voltage in the metal case is overall 0.6 times the reverse voltage polarity against the voltage of the charged object when the volume (depth) of the metal case increases. The result of this study will be helpful for considering the preventive measures of a malfunction or failure of electronic equipment caused by the movement of a charged body.