Hitachi J300U Series Measurement Method for I/O Voltage, Current, and Power, Parts to be measured

10-6

10.3Measurement Method for I/O Voltage, Current, and Power

General measuring instruments for I/O voltage, current, and power are indicated below. The voltage to be measured is the fundamental wave effective voltage and the power to be meas- ured is the total effective value.

R	IR		R	U	IU
(L1)
	ER	W11		General	EU-V
Power S
	IS		S purpose V		IV
supply (L2)				inverter
	ES	W12			EV-W
T	IT		T	W	IW
(L3)
	ET				EW-V

U(T1)

W01

V Motor (T2)

W02

W

(T3)

Table 3 Parts to be measured

Measurement	Parts to be			Measuring instrument	Remarks	Reference
item	measured					value
Supply voltage	Between R and S, S and			Moving-iron type	Fundamental
E1	T, T and R (ER)(ES)(ET)			voltmeter or rectifier	wave effective
				type voltmeter	value
Supply current	R, S, T (IR)(IS)(IT)			Moving-iron type	Total effective
I1				ammeter	value
Supply power	Between R and S, S and			Electrodynamic type	Total effective
W1	T (W11)(W12)			wattmeter	value
Supply power	Calculate the supply power factor from the measured supply voltage, E1,
factor	supply current I1 and supply power W1.
Pf1	Pf1=	W1	× 100 (%)
		3 E1I1

Output voltage	Between U and V, V and
E0	W, W and U
	(EU)(EV)(EW)
Output current	U, V, W (IU)(IV)(IW)
I0
Output power	Between U and V, V
W	and W
0	(W01)(W02)

Rectifier type	Total effective
voltmeter	value
Moving-iron type	Total effective
ammeter	value
Electronic type	Total effective
wattmeter	value

Output power factor

Pf0

Calculate the output power factor from the output voltage E, output current I, and output power W.

Pf0=	W0	× 100(%)
	3 E0I0

NOTE 1: Use a meter indicating a fundamental wave effective value for voltage, and meters indicating total effective values for current and power.

NOTE 2: The inverter output waveform is a distorted wave, and low frequencys may cause errors. However, the measuring instruments and methods indicated above provide comparatively accurate values.

NOTE 3: A tester (general purpose) may not be suited often to measurement of a distorted wave.