Mitsubishi Electric 800 Series, Instruction Manual, Page: 74 / 727

Countermeasures against deterioration of the 600 V class motor insulation
PRECAUTIONS FOR USE OF THE INVERTER
73
3
3.5
Countermeasures against deterioration of
the 600 V class motor insulation
In the PWM type inverter, a surge voltage attributable to wiring constants is generated at the motor terminals. Especially for a
600V class motor, the surge voltage may deteriorate the insulation.
When the 600 V class motor is driven by the inverter, consider the following measures:
 Measures
• Inverter duty motor
Select an inverter duty motor. Many motor manufacturers sell motors with insulation systems designed to withstand the stress
imposed by PWM inverters
• AC reactor
For added protection, install an AC reactor on the inverter output
100%
0
200
150
Voltage at a motor terminal (%)
10 20 30 40 50 60 70 80 90 100
Motor wiring length (m)
Surge voltage at a motor terminal by motor wiring length (reference)