Danfoss VLT AAF006 Service Manual page 3

Contents
3 Internal Active Filter Operation
3.1 General
3.2.2 Control Card
3.2.3 Active Filter Card
3.2.4 Control to Power Interface
3.2.5 Filter Power Section
3.3 Additional Circuitry
3.3.1 AC Contactor
3.3.2 Soft Charge Circuit
3.3.3 Additional Thermal Protection
3.3.4 Current Transducers
3.3.5 Cooling Fans
3.3.6 Fan Speed Control
3.3.7 Low Harmonic Drive
4 Troubleshooting
4.1 Troubleshooting Tips
4.2 Fault Symptom Troubleshooting
4.3 Visual Inspection
4.4 Fault Symptoms
4.4.1 No Display
4.4.2 Intermittent Display
4.5 Warning/Alarm Messages
4.5.1 Warning/Alarm Code List
4.6 After Repair Tests
5 Active Filter and the Power Grid
5.1 Grid Variations
5.1.1 Grid Configurations
5.1.2 Grid Impedance
5.1.3 Voltage Pre-distortions
5.2 Basic Troubleshooting Background
5.2.1 Line Phase Loss and Unbalanced Phase Trips
5.2.2 Voltage Dips and Flickers
5.2.3 Compatibility with Other Equipment on the Same Line Power
5.2.4 Line Power Resonances
5.2.5 Control Logic Problems
5.2.6 Programming Problems
VLT Advanced Active Filter AAF006 D and E Frames Service Manual
®
MG90Z122 - VLT is a registered Danfoss trademark
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