Rev. 1 - 05/10/2021
OPERATING MANUAL
OPERATING MANUAL
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This feature allows to skip the resonance frequencies of the fan installation.
To activate this feature the Holding Register 32 must be set at the desired
Avoid Range Start and the
Holding Register 33 the desired Avoid Range End.
11.6 Skip speed Range (not available for 1.05kW 1-phase)
This function should be avoided when used in close control loops
application or unstable conditions of the fan could occur.
In the following paragraph the starting phase of a fan is shown.
• The first phase when the fan receives a command to start running is the ALIGNMENT. During this phase
the driver aligns the rotor.
• The second phase is the dragging phase, where the fan gradually increases its speed to the minimum
in open loop. In this phase the current and speed values present in the Input Register can’t be taken in
consideration.
• The last phase is the closed loop where the sensorless control is active and from the minimum speed to
the target speed the fan accelerates with different ramps basing on the fan size and the wheel inertia. The
acceleration and deceleration values are different and to avoid overvoltage alarm or loss of synchronism
alarm, the deceleration is always lower.
11.7 Soft start
During the ALIGNMENT and DRAGGING phases a Loss of Synchronism alarm could occur if there is a
condition of wrong rotor starting position or wrong position estimation during the open loop phase.
This is not a blocking alarm; therefore the fan stops and auto-restarts after few seconds.
