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3. Precautions for Use of the Inverter
3.5 Countermeasures against deterioration of the 600 V class motor insulation
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:
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
Surge voltage at a motor terminal by motor wiring length (reference)
100%
0
200
150
V
oltage at a motor terminal (%)
10
20
30
40
50
60
70
80
90
100
Motor wiring length (m)
