Question:
How can a frequency inverter be switched to a blower's motor rotating to the opposite direction of the discharge direction?
Answer:
If the motor is driven to the opposite direction of its discharge direction, e. g. due to an air flow, the frequency inverter can switch off with an overcurrent-message (OCx) when it is connected to the motor.
The flying circuit offers no reliable remedy for this status.
We recommend to decelerate the inertia by means of the DC brake (semi-standstill) and then to start the frequency inverter directly with the output frequency 0 Hz (without flying circuit).
Parameter suggestion:
In connection with the Application I/O this can be realised by the application of a timing element for a digital output.
For this purpose the starting condition, e. g. controller inhibit, is to be connected to an additionally free digital input, e. g. E5, and E5 is to be connected to a digital output, e. g. A1 (setting via C0415/2 = 36).
And A1 is to be connected via a wire bridge to E6, and E6 is to be inverted (C0411 = 32). With E6 the function DC brake is activated (MCTRL-DCB via C0410/15 = 6).
By means of the acceleration time of the digital output (C0423/2) the time of the braking process can be set by a DC brake. The influence of the DC brake can be varied via C0036.
The coasting blower can be decelerated for max. 65 s with the max. value of the DC brake.
=> When using this function please consider the heating of the motor in short intervals.
