Mitsumi electronic 55K, FR-F520-0.75K Measurement of main circuit voltages, currents and power

PROTECTIVE FUNCTIONS

5.3.9 Measurement of main circuit voltages, currents and power

Measurement of voltages and currents

Since the voltages and currents on the inverter power supply and output sides include harmonics, accurate measurement depends on the instruments used and circuits measured.

When instruments for commercial frequency are used for measurement, measure the following circuits using the instruments given on the next page.

Input voltage Output voltage

Input current Output current

	Ar	W11
3-phase		Vr
	As	W12
power
supply		Vs
	At	W13
		Vt

Instrument types

Inverter

R 〈L1〉	U	Au	Vu	W21
S 〈L2〉	V	Av	Vv			To motor
T 〈L3〉	W	Aw	Vw	W22
P 〈+〉 〈 –〉 N					:Moving-iron type
+ V					:Electrodynamometer type
	-				:Moving-coil type
					:Rectifier type

Typical Measuring Points and Instruments

Note: Use an FFT to measure the output voltage accurately. Accurate measurement cannot be made if you use a tester or general measuring instrument.

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