Countermeasures Against Deterioration Of The 600 V Class Motor Insulation - Mitsubishi Electric 800 Series Instruction Manual

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 in a
600 V class motor, the surge voltage may deteriorate the insulation.
When the 600 V class motor is driven by the inverter, consider the following countermeasures:
200
150
100%
0
10 20 30
Surge voltage at a motor terminal by motor wiring length (reference)
 Countermeasures
 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
82
3. Precautions for Use of the Inverter

3.5 Countermeasures against deterioration of the 600 V class motor insulation

40 50 60 70 80
Motor wiring length (m)
90 100