General Inverter Electrical Measurements - Omron 3G3MX2 User Manual

Maintenance and Inspection
6-4-4

General Inverter Electrical Measurements

Note 1
Note 2
Note 3
The following table specifies how to measure key system electrical parame-
ters. The diagrams on the next page show inverter-motor systems and the
location of measurement points for these parameters.
Parameter Circuit location of
measurement
Supply E – across L1 and L2
R
voltage E
1
E – across L2 and L3
S
E – across L3 and L1
T
Supply I - L1
r
current I
1
I - L2
s
I - L3
t
Supply W – across L1 and L2
11
power W
1
W – across L2 and L3
12
Supply
power
factor Pf
1
Output E – across U and V
U
voltage E
O
E – across V and W
V
E – across W and U
W
Output I - U
U
current I
O
I - V
V
I - W
W
Output W – across U and V
O1
power W
O
W – across V and W
O2
Output Calculate the output power factor from the output
power voltage E, output current I, and output power W.
factor Pf
O
Use a meter indicating a fundamental wave effective value for voltage, and
meters indicating total effective values for current and power.
The inverter output has a distorted waveform, and low frequencies may cause
erroneous readings. However, the measuring instruments and methods listed
above provide comparably accurate results.
A general-purpose digital volt meter (DVM) is not usually suitable to measure
a distorted waveform (not pure sinusoid).
Measuring
instrument
Moving-coil Fundamental
type volt- wave effective
meter or value
rectifier type
voltmeter
Total effective
value
Total effective
value
W1
Pf = × 100 %
1
3 × E × I
1 1
Rectifier Total effective
type voltme- value
ter
Moving-coil Total effective
type amme- value
ter
Electronic Total effective
type watt- value
meter
W
1
Pf = × 100 %
O
3 × E × I
O O
Section 6-4
Notes Reference
Value
Commercial
supply volt-
age
200 V class:
200-240 V,
50/60 Hz
400 V class:
380-460 V,
50/60 Hz
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–
–
–
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