Danfoss VLT FC 280 Operating Manual page 51

Operating Guide | VLT® Midi Drive FC 280
4.
Parameter 1-39 Motor Poles.
5.
Parameter 1-30 Stator Resistance (Rs).
Enter line-to-common stator winding resistance (Rs). If only line-to-line data is available, divide the line-to-line value by 2 to
achieve the line-to-common (starpoint) value.
It is also possible to measure the value with an ohmmeter, which also takes the resistance of the cable into account. Divide the
measured value by 2 and enter the result.
6.
Parameter 1-37 d-axis Inductance (Ld).
Enter line-to-common direct axis inductance of the PM motor. If only line-to-line data is available, divide the line-to-line value
by 2 to achieve the line-to-common (starpoint) value.
It is also possible to measure the value with an inductance meter, which also takes the inductance of the cable into account.
Divide the measured value by 2 and enter the result.
7.
Parameter 1-40 Back EMF at 1000 RPM.
Enter line-to-line back EMF of the PM motor at 1000 RPM mechanical speed (RMS value). Back EMF is the voltage generated by
a PM motor when no drive is connected and the shaft is turned externally. Back EMF is normally specified for nominal motor
speed or for 1000 RPM measured between 2 lines. If the value is not available for a motor speed of 1000 RPM, calculate the
correct value as follows:
For example, if back EMF at 1800 RPM is 320 V, the back EMF at 1000 RPM is:
Back EMF=(Voltage/ RPM)x1000=(320/1800)x1000=178
Program this value for parameter 1-40 Back EMF at 1000 RPM.
Testing Motor Operation
5.5.2.3
1. Start the motor at low speed (100–200 RPM). If the motor does not run, check installation, general programming, and motor
data.
Parking
5.5.2.4
This function is the recommended option for applications where the motor is rotating at low speed, for example, windmilling in fan
applications. Parameter 2-06 Parking Current and parameter 2-07 Parking Time are adjustable. Increase the factory setting of these
parameters for applications with high inertia.
Start the motor at nominal speed. If the application does not run well, check the VVC+ PM settings. Recommendations in different
applications are shown in Table
Table 18: Recommendations in Different Applications
Application
Low inertia applications I
Load
Medium inertia applications 50>I
>5
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18.
Settings
(1)
/I <5 • Increase the value for parameter 1-17 Voltage filter time const. by factor 5 to 10.
Motor
• Reduce the value for parameter 1-14 Damping Gain.
• Reduce the value (<100%) for parameter 1-66 Min. Current at Low Speed.
/I Keep calculated values.
Load Motor
Commissioning
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