General Inverter Electrical Measurements - Hitachi SJ300 Series Instruction Manual

General Inverter
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
Electrical
parameters.
Measurements
Parameter
Supply voltage
E
1
Supply current
I
1
Supply power W
1
Supply power
factor Pf
1
Output voltage
E
0
Output current I
o
Output power W
o
Output power
factor Pf
o
Note 1: Use a meter indicating a fundamental wave effective value for voltage, and meters
Note 2: The inverter output has a distorted waveform, and harmonic frequencies may cause
Note 3: A general-purpose digital volt meter (DVM) is not usually suitable to measure a
Circuit location
of measurement
E – across L1 and L2
R
E – across L2 and L3
S
E – across L3 and L1
T
I – L1, I – L2, I – L3
r s t
W – across L1 and L2
11
W – across L2 and L3
12
W
----------------------------- -
=
Pf
1
×
3 E
E – across U and V
U
E – across V and W
V
E – across W and U
W
I – U
U
I – V
V
I – W
W
W – across U and V
01
W – across V and W
02
Calculate the output power factor from the output voltage E, output
current I, and output power W.
----------------------------- -
=
Pf
0
indicating total effective values for current and power.
erroneous readings. However, the measuring instruments and methods listed above
provide reasonably accurate results.
distorted waveform (not pure sinusoid).
Measuring
instrument
Moving-coil type Fundamental
voltmeter or recti- wave effective
fier type voltmeter value
Moving-coil type Total effective
ammeter value
Electronic type Total effective
wattmeter value
1 ×
100%
×
I
1 1
Rectifier type Total effective
voltmeter value
Moving-coil type Total effective
ammeter value
Electronic type Total effective
wattmeter value
W
0 ×
100%
× ×
3 E I
0 0
SJ300 Inverter
Notes Reference Value
Commercial supply
voltage (200V class)
200-240V, 50/60 Hz
400V class 380-
460V, 50/60 Hz
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