Astatic Wattmeter Precision Chauvin & Arnoux (0284)
Info
Meter to measure the power usage of a load. Could be used either for single or 3 phase connections by setting the connector plate. The term astatic indicates that the instrument is build in such a way that the earth's magnetic field does not influence the measurement.
References/Links/More Info
Université de Brest - Instruments Scientifiques