Mitsubishi Electric FR-A720-0.4K Instruction Manual page 447

Measurement of main circuit voltages,
currents and powers
Measuring points and instruments
Item Measuring Point
Across R/L1 and S/L2,
Power supply voltage
S/L2 and T/L3,
V
1
T/L3 and R/L1
Power supply side
R/L1, S/L2, and T/L3
current
line currents
I
1
R/L1, S/L2, T/L3 and
Power supply side
R/L1 and S/L2,
power
S/L2 and T/L3,
P
1
T/L3 and R/L1
Calculate after measuring power supply voltage, power supply side current and power supply side power.
Power supply side
power factor
= ————— × 100%
Pf
Pf
1
1
Across U and V,
Output side voltage
V and W,
V
2
W and U
Output side current U, V and W line
I currents
2
U, V, W and
Output side power
U and V,
P
2
V and W
Calculate in similar manner to power supply side power factor.
Output side power
factor
= ————— × 100%
Pf
2
Pf
2
Converter output Across P/+ and N/−
Across 2, 4(+) and 5
Frequency setting
signal
Across 1(+) and 5
Across 10 (+) and 5
Frequency setting
power supply
Across 10E(+) and 5
Across AM(+) and 5
Frequency meter
signal
Across FM(+) and SD
Across SD and the
Start signal following: STF, STR,
Select signal RH, RM, RL, JOG, RT,
AU, STOP, CS (+)
Reset Across RES (+) and SD
Output stop Across MRS (+) and SD
Across A1and C1
Fault signal
Across B1and C1
*1 Use an FFT to measure the output voltage accurately. A tester or general measuring instrument cannot measure accurately.
*2 When the carrier frequency exceeds 5kHz, do not use this instrument since using it may increase eddy-current losses produced in metal parts
inside the instrument, leading to burnout. If the wiring length between the inverter and motor is long, the instrument and CT may generate heat
due to line-to-line leakage current.
*3 When the setting of Pr. 195 ABC1 terminal function selection is positive logic
*4 A digital power meter (designed for inverter) can also be used to measure.
436
Measuring Instrument
Moving-iron type AC voltmeter
Moving-iron type AC ammeter
Digital power meter (designed for
inverter) or electrodynamic type
single-phase wattmeter
P
1
× I
V
3
1 1
Rectifier type AC voltage meter
(Moving-iron type cannot
measure)
Moving-iron type AC ammeter
Digital power meter (designed for
inverter) or electrodynamic type
single-phase wattmeter
P
2
× I
V
3
2 2
Moving-coil type (such as tester) Inverter LED display is lit. 1.35
Moving-coil type
(Tester and such may be used)
(Internal resistance: 50kΩ or
Moving-coil type
(such as tester)
Remarks (Reference Measured Value)
Commercial power supply
Within permissible AC voltage fluctuation
*4
(Refer to page 444)
*4
P1=W11+W12+W13 (3-wattmeter method)
*1*4
Difference between the phases is within ±1% of
the maximum output voltage.
Difference between the phases is 10% or lower
*2*4
of the rated inverter current.
P = W
2
2-wattmeter method (or 3-wattmeter method)
0 to 10VDC, 4 to 20mA
0 to ±5VDC, 0 to ±10VDC
5.2VDC
10VDC
Approximately 10VDC at maximum
frequency (without frequency meter)
Approximately 5VDC at maximum
frequency
(without frequency meter)
larger)
Pulse width T1:
Pulse cycle T2: Set by Pr. 55
When open
20 to 30VDC
ON voltage: 1V or less
Conduction check
Across A1 and C1 No conduction
Across B1 and C1
+ W
21 22
×
V1
T1
8VDC
T2
Adjusted by C0 (Pr. 900)
(Valid for frequency
monitoring only)
*3
<Abnormal>
Conduction No conduction
"5" is
common
"SD" is
common
<Normal>
Conduction