Chapter 5 Troubleshooting
VFD-EL-W
5-12
5.14 Affecting Other Machines
An AC motor drive may affect the operation of other machines due to many reasons. Some solutions are listed
below:
High Harmonics at Power Side
You can reduce high harmonics at the power side during running.
1. Separate the power system: use a transformer for the AC motor drive.
2. Use a reactor at the power input terminal of the AC motor drive.
3. If using phase lead capacitors (never on the AC motor drive output!), use serial reactors to prevent
damage to the capacitors from high harmonics.
serial reactor
phase lead capacitor
Motor Temperature Rises
When the motor is a standard induction motor with a fan, the cooling will be insufficient at low speed,
causing the motor to overheat. In addition, high harmonics at the output increases copper and core
losses. Use the following measures depending on load and operation range.
1. Use a motor with independent ventilation (forced external cooling) or increase the motor rated power.
2. Use a special inverter-duty motor.
3. Do NOT run at low speed for long periods of time.
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