GF312B portable three phase watt meter calibrator with printer is used to calibrate three phase, single phase, active and reactive watt meters. And it also can be used as voltage, current and power meter to measure AC parameters of three phase power line.It can measure wave distortion factor and 2nd to 63th harmonic wave. •Three phase active or reactive electricity energy meter •Calibrate three phase, single phase, active or reactive meter error •Measure U(voltage) of three phase or single phase •4Measure I(current) of three phase or single phase •Measure active power of three phase or single phase •Measure reactive power of three phase or single phase •Measure apparent power of three phase or single phase •Measure power factor of three phase or single phase •Measure phase angle between voltage and current •Measure frequency of power line •Display vector diagram •Display waveform of U and I •Analyze and display content of harmonic of U and I •Store and check measured data •Optional 5A, 20A, 100A, 500A, 1000A, 2000A, 3000A current clamp •Measure CT variable ratio •Print the data of measurement on site