HERSTEL EN OPWAARDERING KELVIN ELEKTROSTATISCHE VOLTMETER N° 6144-A
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The operating principle of an electrostatic voltmeter is similar to that of an electrometer, it is, however, designed to measure high potential differences; typically from a few hundred to many thousands volts.
Principle of operation
Electrostatic voltmeter utilizes the attraction force between two charged surfaces to create a deflection of a pointer directly calibrated in volts. Since the attraction force is the same regardless of the polarity of the charged surfaces (as long as the charge is opposite), the electrostatic voltmeter can measure both direct current and alternating current.
Typical construction is shown in the engraving. The pivoted sector NN is attracted to the fixed sector QQ. The moving sector indicating the voltage by the pointer P and is counterbalanced by the small weight w. In newer instruments the weight is replaced by a spring, thus allowing the meter to be used both in horizontal and vertical positions. This form of design is shown in the photograph of the mechanism. The fixed sector is insulated from the rest of the meter. The butterfly shaped moving sector, made out of a thin aluminum foil, is pivoted below. Both the fixed and the moving sectors are highly polished and without any sharp corners to minimize high electrical stress areas. The movement of the sector is damped by the air vane attached by a curved piece of wire.
Bron (werking): Wikipedia
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