8.6.3 Adjustment of the U/f curve
Information
The device comes supplied with a preprogrammed square characteristic curve for the operation of
fans.
In the case of voltage-controllable motors and square load torque-moments (e.g. fans and pump
operation), an optimal speed control is generally achieved through this.
In systems in which high dynamics are required, switchover to a linear characteristic must take place.
Generally speaking, if the load characteristic is not known as a definite value, the linear characteristic
should be set. In the case of linear characteristic curves, the motor achieves full torque throughout the
entire speed range. For this, a thermal overload of the motor must be prevented through suitable
measures (complete motor protection through using thermocontact or PTC thermistor-monitoring).
Edgefrequency
Edgefrequency
The maximum output voltage is attained during break edge frequency.
Adjustment range: 1.0 - 120.0 Hz
Factory setting: 48.5 Hz
In the case of special settings with “Edge frequency” > “Max. Frequency”, due to higher
power losses it is possible that automatic power reduction occurs (
Messages and
trouble shooting “Temp. Manager”).
Max. Frequency
Max. Frequency
Above the Edgefrequency, the frequency is merely increased up to the Maximum
frequency.
Adjustment range: 1.0 - 120 Hz
Factory setting: 50.0 Hz
Uout Output voltage
Fout: Output frequency
Analog In Speed setting signal (0 - 10 V, 0...20 mA, 0...100 % PWM)
Ustart Startvoltage
Foff Shutdown Freq.
Fon: Switch on Freq.
Fedge Edgefrequency
Fmax Max. Frequency
L linear
Q Square (factory setting)
Due to technical reasons the output voltage amounts to approx. max. 95 % of the applied mains
voltage.
In order to still be able to achieve the maximum airflow of the connected fans, an increase of the
maximum frequency is possible for our motors. For this, a current increase must be included in the
calculation. It is necessary to optimize monitoring of motor current, output voltage, and speed using
suitable measuring instruments.
Operating Instructions Fcontrol Basic – model series FSDM2.5..50AM Programming
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