Power factor matching in an AC power meter

摘要

A solid-state AC energy consumption meter includes an array of AC signal transducers which provide voltage and current signals to a watt transducer chip. The watt transducer chip operates on the multi-phase voltage and current signals to produce AC energy consumption data which is fed to a register for visual display. In one aspect of the invention, a calibrating resistive component is placed in series with the input to the primary coil of the potential transformer for each phase. The value of the resistive component is calibrated to produce an appropriate change in the phase angle difference between the potential transformer secondary voltage and current transformer secondary current. More particularly, the addition of the resistance of the primary of the potential transformer provides the necessary amount of phase lead to the potential transformer to account for this phase error difference.