LIGHT-LOAD COMPENSATION ADJUSTING DEVICE OF INDUCTION TYPE WATTHOUR METER

摘要

PURPOSE:To compensate well a negative error characteristic in a light-load region by generating a minute torque on a rotary disc in the same direction as a driving torque from a compensating coil wound around a voltage iron core to a compensating coil wound around a current iron core. CONSTITUTION:An induced current (compensating current) due to a relatively stable voltage magnetic flux or applied voltage is flowed to a part or the whole of a small amount of compensating coil 23 or a current coil wound around a current iron core 21. By this light-load compensation, the compensating effect is enhanced according as the light-load region, where the term that the resistance of a compensating current circuit is changed in accordance with the square of the current approximately is included and it functions as an inverse proportional element to the rotative force of a disc 30, is more light-load and the power-factor is reduced; and thus, the current characteristic having a negative error inclination is improved in the low power-factor region is improved independently of power-factor.