Design and development of new electrostatic voltmeter using strain gauge

This 50 kV class voltmeter accurately detects the displacement of a thin plate of phosphor bronze in the movable electrode, to which the foil gauges are attached, when DC and AC voltages are applied between the fixed and movable electrodes. The movable aluminum-disc electrode and a strain beam are designed, and an electrostatic voltmeter of 50 kV class and higher is manufactured for trial. The relation between the mechanical system part of the movable electrode and the strain on the strain beam is analyzed mathematically. From the results obtained from the relation between the strain on the strain beam and applied voltage, it is ascertained that the strain varied proportionally to the square of the electric stress between the fixed and movable electrodes. A comparison of experimental results to theoretical values is presented