6-1 Inspection and Maintenance „ Measurement Methods of I/O Voltage, Current, and Electric Power Below is a general measurement device for input/output voltages, current, and electric power. R I R W 11 R/L1 U/T1 I U W 01 U E R E U Power supply S I S W 12 S/L2 Inverter I V V V/T2 Motor T E S E V W I T E T W 13 T/L3 W/T3 I W E W W 02 6 Inspection and Maintenance 6-9 Measurement item Measurement point Measurement device Note Measurement value reference Power supply voltage EIN Between R-S, S-T, and T- R (ER), (ES), (ET) Moving-iron voltmeter or Rectifier voltmeter All effective values 200-V class: 200 to 240 V, 50/60 Hz 400-V class:
380 to 480 V, 50/60 Hz Power supply current IIN Current R, S, T (IR), (IS), (IT) Moving iron ammeter All effective values When the input current is not balanced IIN = (IR+IS+ IT)/3 Input electric power WIN Between R-S, S-T, and T-R (WI1) + (WI2) + (WI3) Electrodynamic wattmeter All effective values Three-wattmeter method Input power factor PfIN Calculated from the measured values of power supply voltage EIN, power supply current IIN, and input electric power WIN.
WIN PfIN = × 100(%) 3 ⋅ EIN ⋅ IIN Output voltage EOUT Between U-V, V-W, W-U (EU), (EV), (EW) See the figure below or Rectifier voltmeter Effective value of fundamental wave Output current IOUT Current U, V, W (IU), (IV),(IW) Moving iron ammeter All effective values Output power WOUT Between U-V, V-W (WO1)+(WO2) Electrodynamic wattmeter All effective values Two-wattmeter method (or three-wattmeter method) Output power factor PfOUT Calculated from the measured values of output voltage EOUT, output current IOUT, and output power WOUT. WOUT PfOUT = × 100(%) 3 ⋅ EOUT ⋅ IOUT