Measurement Method Of I/O Voltage, Current, And Power - Hitachi SJ Series User Manual

Chapter 19
19.9 Measurement Method of I/O
Voltage, Current, and Power
The following shows general measurement
instruments used for measurement of input/output
voltage, current, and power.
R
IR
S
Power
IS
supply
T
IT
Measurement
Target section
item
Power supply
Between R-S, S-T, and T-R
voltage
(E ), (E ), (E
R S
E
IN
Power supply Current of R, S, and T
current (I ), (I ), (I )
R S T
I
IN
Power from
Between R-S, S-T, and T-R
power supply
(W )+(W )+(W
I1 I2
W
IN
This value is calculated using measurement values of power supply voltage E
Power rate of supply current I
power supply
P
fIN
Output
Between U-V, V-W, and W-U
voltage
(E ), (E ), (E
U V
E
OUT
Output current Current of U, V, and W
I (I ), (I ), (I )
OUT U V W
Output power Between U-V and V-W
W (W )+(W )
OUT O1 O2
This value is calculated using measurement values of output voltage E
Output power current I , and output power W
OUT
factor
P
fOUT
Measurement method of output voltage
R
S
T
Diode
600V 0.1A or above (200V class)
1000V 0.1A or above (400V class)
Effective value of fundamental
wave VAC
VAC=1.1×VDC
WI1
ER
WI2
ES
WI3
ET
Measurement instrument
Moving iron voltmeter
)
T
Rectifier type voltmeter
Moving iron ammeter
Electrodynamometer type
) wattmeter
I3
, and power supply power W
IN
See the figure below
)
W
Rectifier type voltmeter
Moving iron ammeter
Electrodynamometer type
wattmeter
.
OUT
U
V
W
2W 220kΩ
Maintenance and Inspection
R U
IU
Inverter
S V
IV
T
W
IW
Remarks
All effective values
or
All effective values
All effective values
.
IN
W
IN
P =
fIN
√3・E ・I
IN IN
Effective value of
or
fundamental wave
All effective values
All effective values
, output
OUT
W
OUT
P =
fOUT
√3・E ・I
OUT OUT
Motor
+
VDC
Moving coil type
－
300V (200V class)
600V (400V class)
19-7
U
WO1
EU
V
EV
W
WO2
EW
Criteria
200V class: 200-240V 50/60Hz
400V class: 380-500V 50/60Hz
If input current is imbalanced
I =(I +I +I )/3
IN R S T
Three wattmeter method
, power
IN
×100
Two wattmeter method
(or three wattmeter method)
×100
Note)
1. Use an instrument that
indicates effective values of
fundamental wave for output
voltage, and use instruments
that indicate all effective values
for current and power.
2. The output waveform of
inverter generates errors
especially at low frequency
because it is a waveform
control by PWM. Take care
because a tester
(general-purpose product) may
not be adapted due to noise.
Motor