263
Measurement of main circuit voltages, currents and powers
6
PRECAUTIONS FOR MAINTENANCE AND INSPECTION
Measuring Points and Instruments
Item Measuring Point Measuring Instrument Remarks (Reference Measured Value)
Power supply voltage
V
1
R/L1 and S/L2
S/L2 and T/L3
T/L3 and R/L1
Moving-iron type AC
voltmeter ∗3
Commercial power supply
Within permissible AC voltage fluctuation (Refer to
page 268)
Power supply side
current
I
1
R/L1, S/L2, T/L3 line
current
Moving-iron type AC
ammeter ∗3
Power supply side
power
P
1
R/L1, S/L2, T/L3 and
R/L1 and S/L2,
S/L2 and T/L3,
T/L3 and R/L1
Digital power meter
(designed for inverter) or
electrodynamic type single-
phase wattmeter
P
1=W11+W12+W13 (3-wattmeter method)
Power supply side
power factor
Pf
1
Calculate after measuring power supply voltage, power
supply side current and power supply side power.
Output side voltage
V
2
Across U and V, V and W,
and W and U
Rectifier type AC voltage
meter ∗1 ∗3
(moving-iron type cannot
measure)
Difference between the phases is within 1% of the
maximum output voltage.
Output side current
I
2
U, V and W line currents
Moving-iron type AC
ammeter ∗3
Difference between the phases is 10% or lower of
the rated drive unit current.
Output side power
P
2
U, V, W and
U and V, V and W
Digital power meter
(designed for inverter) or
electrodynamic type single-
phase wattmeter
P
2 = W21 + W22
2-wattmeter method (or 3-wattmeter method)
Output side power
factor
Pf
2
Calculate in similar manner to power supply side power factor.
Converter output Across P/+ and N/-
Moving-coil type
(such as tester)
Drive unit LED display is lit. 1.35 × V1
Frequency setting
signal
Across 2(+) and 5
Moving-coil type
(tester and such may be
used)
(internal resistance 50kΩ or
more)
0 to 10VDC, 4 to 20mADC
"5" is
common
Across 4(+) and 5
Frequency setting
power supply
Across 10(+) and 5 5.2VDC
Frequency meter
signal
Across FM(+) and SD
Approximately 5VDC at maximum
frequency
(without frequency meter)
Pulse width T1 : Adjust with C0 (Pr.
900)
Pulse cycle T2 : Set with Pr. 55
(frequency monitor only)
"SD" is
common.
Start signal
Select signal
Across SD and STF, STR,
RH, RM, or RL(+)
When open
20 to 30VDC
ON voltage: 1V or less
Fault signal
Across A and C
Across B and C
Moving-coil type
(such as tester)
Continuity check ∗2
<Normal><Fault>
Across A and C Discontinuity Continuity
Across B and C Continuity Discontinuity
∗1 Use an FFT to measure the output voltage accurately. An FA tester or general measuring instrument cannot measure accurately.
∗2 When the setting of Pr. 192 A,B,C terminal function selection is positive logic
∗3 A digital power meter (designed for inverter) can also be used to measure.
Pf1
P1
3V1 I× 1
------------------------
100×=
%
Pf2
P2
3V2 I2×
------------------------
100×=
%
8VDC
T1
T2
