Inverter-Driven 400V Class Motor - Mitsubishi Electric FR-F500 Instruction Manual

( 2 ) Line-to-line leakage currents
Harmonics of leakage currents flowing in static capacities between the inverter output cables might operate
the external thermal relay unnecessarily.
Power
supply
Countermeasures
• Use the electronic overcurrent protection (Pr. 9) of the inverter.
• Decrease the carrier frequency. Note that the audible motor noise increases. Selection of Soft-PWM (Pr.
240) will make it unoffending.
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.

2.3.10 Inverter-driven 400V class motor

In the PWM type inverter, a surge voltage attributable to wiring constants is generated at the motor terminals.
Especially for a 400V class motor, the surge voltage may deteriorate the insulation. When the 400V class
motor is driven by the inverter, consider the following measures:
• • • • Measures
It is recommended to take either of the following measures:
(1) Rectifying the motor insulation
For the 400V class motor, use an insulation-rectified motor. Specifically,
1) Specify the "400V class inverter-driven, insulation-rectified motor".
2) For the dedicated motor such as the constant-torque motor and low-vibration motor, use the "inverter-
driven, dedicated motor".
(2) Suppressing the surge voltage on the inverter side
On the secondary side of the inverter, connect the optional surge voltage suppression filter (MT-BSL/BSC).
NFB Thermal relay
Inverter
Line static capacitances
Line-to-Line Leakage Current Path
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INSTALLATION AND WIRING
Motor
IM
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