Mitsubishi Electric FR-D720S SC EC, Инструкция по эксплуатации

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Wiring Electromagnetic compatibility (EMC)
FR-D700 SC EC 3 - 45
The leakage current of the 200V class is about a half.
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Countermeasures
– Use Pr. 9 "Electronic thermal O/L relay".
– If the carrier frequency setting is high, decrease the Pr. 72 "PWM frequency selection"
setting. Note that motor noise increases. Selecting Pr. 240 "Soft-PWM operation selec-
tion" makes the sound inoffensive. To ensure that the motor is protected against line-to-
line leakage currents, it is recommended to use a temperature sensor (e.g. PTC element)
to directly detect motor temperature.
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Selecting a power supply circuit breaker:
You can also use a circuit breaker (MCCB) to protect the power supply lines against short
circuits and overloads. However, note that this does not protect the inverter (rectifiers, IGBT).
Select the capacity of the circuit breaker on the basis of the cross-sectional area of the power
supply lines. To calculate the required mains current trip point you need to know the power
required by the inverter (Refer to Rated Input Capacity in Appendix A, Specifications) and
the mains supply voltage. Select a circuit breaker with a trip point that is slightly higher than
calculated, particularly in the case of breakers with electromagnetic tripping, since the trip
characteristics are strongly influenced by the harmonics in the power supply line.
Example
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Line-to-line leakage current data example
Dedicated motor: SF-JR 4P
Carrier frequency: 14.5kHz
Used wire: 2mm², 4 cores, cab tyre cable
Motor Capacity [kW] Rated Motor Current [A]
Leakage Currents [mA]
Wiring Length 50m Wiring Length 100m
0.4 1.1 620 1000
0.75 1.9 680 1060
1.5 3.5 740 1120
2.2 4.1 800 1180
3.7 6.4 880 1260
5.5 9.7 980 1360
7.5 12.8 1070 1450
Tab. 3-21: Line-to-line leakage current data example (400V class)
I001043E
Fig. 3-36: Line-to-line leakage currents
NOTE The earth leakage breaker must be either a Mitsubishi earth leakage breaker (ELB, for har-
monics and surges) or an ELB with breaker designed for harmonic and surge suppression
that is approved for use with frequency inverters.
Power
supply
Inverter
Line-to-line
leakage currents
path
Line-to-line static
capacitances
M
3~
Thermal
relay
Motor