6-1 Inspection and Maintenance 6 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. Use the above measurement devices and methods to ensure accuracy. Note 3: General-purpose testers are not applicable for measurement in many cases.
Inspection and Maintenance 6-6 Measurement item Measurement point Measurement device Note Measurement value reference Input power factor Pf I Calculated from the measured values of power supply voltage E, power I 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 electric 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 current I , O O and output electric power W . O W Pf o= Eo × 100 (%) 3 I o o