6-1 Inspection and Maintenance Measurement Methods of I/O Voltage, Current, and Electric Power Below are general measurement devices for I/O voltage, current, and electric power. Measure effective values of fundamental wave for voltage, and all effective values for electric power. General-purpose Inverter U Power supply R I R R/L1 U/T1 I U E R W 11 E U-V W 01 V S I S S/L2 V/T2 I V Motor E S W 12 E V-W W 02 W T I T T/L3 W/T3 I W E T E W-U 6 Inspection and Maintenance Note 1: For voltage, use a measurement device that displays effective values of fundamental wave. For current and electric power, use a measurement device that displays all effective values. Note 2:
The Inverter output waveform, under PWM control, may have a margin of error, especially at a low frequency. Therefore, use the above shown measurement devices and methods to ensure accuracy. Note 3: General-purpose testers are not applicable for measurement in many cases.
6-6 Measurement item Measurement point Measurement device Note Measurement value reference Power supply voltage E I Phase-to-phase voltage between R-S, S-T, and T- R (ER) (ES) (ET) Moving-iron voltmeter or Rectifier voltmeter Effective value of fundamental wave Commercial current (200-V class) 200 to 240 V, 50/60 Hz (400-V class) 380 to 480 V, 50/60 Hz Power supply current I I Current R, S, T (IR) (IS) (IT) Moving-iron ammeter All effective values Input electric power W I Between R-S, S-T (W11) + (W12) Electrodynamic wattmeter All effective values Two-wattmeter method Input power factor Pf I Calculated from the measured values of power supply voltage E, I power supply current I, and input electric power W.
I I W Pf I= EI 100 (%) 3 I I I Output voltage E O Between U-V, V-W, W-U (EU) (EV) (EW) Rectifier voltmeter All effective values Output current I O Current U, V, W (IU) (IV) (IW) Moving-iron voltmeter All effective values Output power W O Between U-V, V-W (W01) + (W02) Electrodynamic wattmeter All effective values Two-wattmeter method Output power factor Pf O Calculated from the measured values of output voltage E , output O current I , and output electric power W . O O