Effect of the power factor on electrostatic wattmeters

Conclusions

• 1. The negligibly small intrinsic angular error of an electronic wattmeter (not counting the external conversion circuits) provides the possibility of applying an exceptionally simple technique for determining the deviation of its pointer from zero for a phase difference of 90°.

• 2. In the suggested technique the deviation of the instrument pointer from zero is determined as the algebraic half-sum of two deflections, one of which is read with a phase difference angle slightly smaller than 90°, and the other after reversing the phase of one of the voltages.

• 3. The method of reversing the phase at a phase difference approaching 90° can be applied for determining the deviation of the pointer from zero in all cases when the intrinsic angular error of the instrument can be neglected, or when it is desired to determine the deviation which is not due to phasing in instruments having a large intrinsic error.

• 4. This technique can be used for investigating, as functions of the deflection angle, the deviations which are not due to phasing, by setting the pointer by means of the corrector to the required mark on the scale.