Mitsubishi Electric FR-E700 Instruction Manual page 73

Wiring
Example 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]
Tab. 3-17: Line-to-line leakage current data example
Fig. 3-29: Line-to-line leakage currents
● 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.
● 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.
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.
FR-E700 EC
Rated Motor Current [A]
0.4
0.75
1.5
2.2
3.7
5.5
7.5
Power
supply
Wiring lenght 50m
1.1
1.9
3.5
4.1
6.4
9.7
12.8
Thermal
relay
Inverter
Electromagnetic compatibility (EMC)
Leakage Currents [mA]
Wiring lenght 100m
620
680
740
800
880
980
1070
Line-to-line
leakage currents
Motor
path
M
3~
Line-to-line static
capacitances
1000
1060
1120
1180
1260
1360
1450
I001043E
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