Hitachi J300U Series Instruction Manual page 87

10.3 Measurement 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
(L1)
Power
S
(L2)
supply
T
(L3)
Measurement
item
Supply voltage
Between R and S, S and
T, T and R (E
E
1
R, S, T (I
Supply current
I
1
Between R and S, S and
Supply power
T (W
W
1
Supply power Calculate the supply power factor from the measured supply voltage, E
factor supply current I
Pf
1
Output voltage Between U and V, V and
W, W and U
E
0
(E
Output current U, V, W (I
I
0
Output power Between U and V, V
and W
W
0
(W
Output power Calculate the output power factor from the output voltage E, output current I,
and output power W.
factor
Pf
0
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.
I
R
E
R
I
S
E
S
I
T
E
T
Table 3 Parts to be measured
Parts to be
measured
)(E )(E )
R S T
)(I )(I )
R S T
)(W )
11 12
and supply power W
1
W
1
Pf =
1
3 E I
1 1
)(E )(E )
U V W
)(I )(I )
U V W
)(W )
01 02
W
0
Pf =
0
3 E I
0 0
R
U
W
11
General
purpose
S
V
inverter
W
12
T
W
Measuring instrument
Moving-iron type
voltmeter or rectifier
type voltmeter
Moving-iron type
ammeter
Electrodynamic type
wattmeter
.
1
Rectifier type
voltmeter
Moving-iron type
ammeter
Electronic type
wattmeter
10-6
I
U
W
E
01
U-V
V
I
V
(T2)
E
W
V-W 02
W
I
W
(T3)
E
W-V
Remarks
Fundamental
wave effective
value
Total effective
value
Total effective
value
,
1
Total effective
value
Total effective
value
Total effective
value
U(T1)
Motor
Reference
value