Electro-magnetic interference (EMI) and leakage currents
Line-to-line leakage current example (200 V class)
Motor: SF-JR 4P
Carrier frequency: 14.5 kHz
Cable: 2 mm
Motor capacity [kW]
The leakage currents of the 400 V class are about twice as large.
– 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 selection" makes the
To ensure that the motor is protected against line-to-line leakage currents, it is recommended
to use a temperature sensor to directly detect motor temperature.
● Installation and selection of the molded case circuit breaker
Install a molded case circuit breaker (MCCB) on the power receiving side to protect the wiring at
the inverter input side. Select an MCCB according to the inverter input side power factor, which
depends on the power supply voltage, output frequency and load. Especially for a completely
electromagnetic MCCB, a slightly large capacity must be selected since its operation characteristic
varies with harmonic currents. (Check it in the data of the corresponding breaker.) As an earth
leakage current breaker, use the Mitsubishi earth leakage current breaker designed for harmonics
and surge suppression.
3 - 2
, 4 cores
Rated motor current [A]
Line-to-line leakage current data example
Line-to-line leakage currents
Wiring length 50 m
Precautions for use of the inverter
Leakage current [mA]
Wiring length 100 m