Hitachi SJ7002 Series Instruction Manual page 272

General Inverter
Electrical
Measurements
Parameter
Supply voltage
Supply current
Supply power W
Supply power
factor Pf
Output voltage
Output current I
Output power W
Output power
factor Pf
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The following table specifies how to measure key system electrical parameters. The diagrams
on the next page show inverter-motor systems and the location of measurement points for these
parameters.
Circuit location
of measurement
E – across L1 and L2
R
E
E – across L2 and L3
1
S
E – across L3 and L1
T
I – L1, I – L2, I
r s
I
1
W – across L1 and L2
1 11
W – across L2 and L3
12
Pf
1
1
E – across U and V
U
E
E – across V and W
0
V
E – across W and U
W
I – U
o U
I – V
V
I – W
W
W – across U and V
o 01
W – across V and W
02
Calculate the output power factor from the output voltage E, output
current I, and output power W.
o
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 has a distorted waveform, and harmonic frequencies may cause
erroneous readings. However, the measuring instruments and methods listed above
provide reasonably accurate results.
Note 3: A general-purpose digital volt meter (DVM) is not usually suitable to measure a
distorted waveform (not pure sinusoid).
Measuring
instrument
Moving-coil type
voltmeter or recti-
fier type voltmeter
– L3 Moving-coil type
t
ammeter
Electronic type
wattmeter
W
1 ×
----------------------------- -
= 100%
× ×
3 E I
1 1
Rectifier type
voltmeter
Moving-coil type
ammeter
Electronic type
wattmeter
W
0 ×
----------------------------- -
Pf = 100%
0
× ×
3 E I
0 0
SJ700 Inverter
2
Notes Reference Value
Fundamental Commercial supply
wave effective voltage (200V class)
value 200-240V, 50/60 Hz
400V class 380-
460V, 50/60 Hz
Total effective
value
Total effective
value
Total effective
value
Total effective
value
Total effective
value
6–25
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