14
9.2. Fans with variable speed
Warning
Resonance frequencies can result in increased vibrations in certain speed ranges. These vibrations can destroy
components.
•
Operate the fan only outside these speed ranges.
•
Run through these speed ranges so quickly that no vibration can exceed the values for the resonance frequency.
•
The operating instructions for the frequency converter must be observed.
Caution
Damage due to incorrect commissioning of the frequency converter.
•
Fan and frequency converter must be installed as close to each other as possible.
•
Use shielded cables.
•
All components (fan, frequency converter and motor) must be earthed.
•
All-pole sine filters must be used. (Exceptions are fans with IEC standard motors. This is not mandatory for these
motors, but is recommended by Walpol.)
•
Fan operation with frequency converters below 10 Hz must be avoided.
•
The heating of the motor when using a frequency converter must be checked by the customer in the application.
•
Never exceed the maximum impeller speed specified on the type plate of the fan.
Caution
Damage due to non-use of a sine filter.
Walpol always recommends an all-pole sine filter when the fan is operated with a frequency converter.
10. Commissioning
The warranty is only valid if commissioning has been carried out correctly and written proof of this has been
provided.
Safety instructions
Commissioning may only be carried out by appropriately qualified persons, for details see table Qualification
Prerequisites
• Assembly and electrical connection have been
completed properly.
• Inlet and outlet are clear.
• Residual material from the installation and foreign
bodies have been removed from the fan and ducts.
• The cable glands have been tightened.
• Check the fan for visible damage before switching
it on and ensure that the protective devices are
functioning properly.
• The data on the type plate correspond to the
connection data.
• Use all locking screws.
• The safety devices have been fitted.
• Permanently install a disconnecting device in the
electrical installation (all-pole contact opening
min. 3 mm).
