Danfoss VACON NXI High Power Frequency Inverter Operation Manual

2.2 Electrical Connections and Cable Selection

Electrical connection is one of the most technologically advanced links, directly related to the electromagnetic compatibility and operational safety of the system.

Cable selection: The manual provides a detailed cable selection table, including recommended cross-sections and types for power cables, motor cables, and control cables. For example, for the FI9 model with a voltage level of 380-500V and an output current of 300A, the recommended motor cable is copper core 3 × 95+50 mm ² or aluminum core 3 × 120+70 mm ². All cables must meet the minimum temperature resistance requirement of 70 ° C.

Grounding and EMC: The manual emphasizes the importance of using grounding conductors that meet the requirements, and recommends using a 360 ° ring grounding method to handle the motor cable shielding layer for optimal EMC performance. For EMC level C4, it is particularly necessary to use cable clamps at the motor end to achieve 360 ° grounding of the shielding layer.

Fuse selection: It is recommended to use aR type (semiconductor protection) or gR type fuses. The manual provides Bussmann fuse models and quantities for different models and voltage levels. For example, the FI12 model requires 2 x 2 170M85473SHT 690V 1250A fuses.

2.3 Control unit and fiber optic connection

For high-power models (FI9 and above), the control unit and power unit communicate through optical fibers to achieve electrical isolation and high-speed data transmission.

Control unit structure: The control unit includes a basic I/O board (OPTA1) and up to 5 optional slots for expanding I/O or fieldbus communication.

Fiber optic connection: The manual provides a detailed description of the connection method for fiber optic cables, including the minimum bending radius (50 mm) and maximum length (8 m). It is particularly emphasized that fiber optic connections must be strictly numbered, as incorrect connections can damage power electronic components.

24V external power supply: The control unit supports power supply through an external 24V power supply, so that parameter settings and monitoring can still be performed even when the main power supply is disconnected. But the manual also points out that when multiple frequency converters are connected in parallel using a 24V power supply, diodes should be connected in series on the 24V input line of each frequency converter to prevent current backflow.

Part Three: Control Panel Operation and Parameter Configuration

The operation panel of VACON NXI is the core interface for users to interact with the frequency converter, providing comprehensive parameter settings and monitoring functions.

3.1 Menu Structure Navigation

The menu system structure of the control panel is clear, divided into several main menus:

M1: Monitoring menu: Used for real-time viewing of key operating data such as output frequency, motor current, speed, torque, voltage, etc. The data is updated every 0.3 seconds.

M2: Parameter menu: Used to set and modify all application parameters. Parameters are grouped by function (e.g. G2.1 is the basic parameter of the motor), and users can navigate and edit them through the up and down browsing keys and left and right menu keys.

M3: Keyboard Control Menu: Used to select control modes (I/O terminals, keyboard or fieldbus), set keyboard frequency settings, change motor direction, and enable/disable stop button functionality.

M4: Current Fault Menu: Display the currently active faults. If there is a fault, the display screen will show the fault code, brief description, and fault symbol (FAULT or ALARM).

M5: Fault History Menu: Record the last 30 faults that have occurred and arrange them in chronological order. Users can view detailed data records (fault time records) for each fault occurrence, including key information such as output frequency, motor current, DC bus voltage, etc. at that time.

M6: System menu: includes advanced functions such as language selection, application selection, parameter backup, password settings, hardware settings, etc.

M7: Expansion Board Menu: Used to view and manage optional I/O boards or communication boards installed in the control unit slot.

3.2 Key parameter settings and functions

Application selection: The VACON NX series comes with a variety of built-in application macros, such as "Basic Applications", "PID Control Applications", "Multi speed Applications", etc. Users can switch applications through the M6.2 menu, and after switching, all parameters will be restored to the default values of the application.

Parameter backup and recovery: The M6.3 menu provides powerful parameter management functions. Users can save all current parameters as a custom parameter set (Set1/Set2), upload parameters to keyboard memory, or download parameters from the keyboard to another frequency converter, which is very convenient for batch debugging and maintenance.

Password protection: To prevent unauthorized parameter modification, the system menu (M6.5) supports setting passwords. The password can be any number between 1 and 65535, and it is required to enter the password when entering the security menu or modifying key parameters after setting.