Year: 2024

In industrial automation control systems, inverters serve as critical devices for power transmission control, and their stability and reliability are directly related to the continuous operation of production lines. The Zhongchen Inverter NZ200 series, as a high-performance option, may encounter specific alarm codes during operation, particularly the OC (Over-Current) alarm.

For short-duration, high-current OC alarms in the NZ200 series, the primary causes generally stem from issues within the current detection circuit of the drive board or potential damage to the module itself. These alarms may recur even after a reset due to underlying issues. Typically, the root causes can be attributed to the following scenarios:

1. Excessively Long Motor Cables: Long motor cables can introduce excessive leakage current, potentially triggering the OC alarm.
2. Inadequate Cable Selection: Choosing marginal cable types can also result in higher leakage currents, especially under high load conditions.
3. Loose Cable Connections and Damage: Loose cable connections or damaged cables can cause arcing effects when the load current surges, triggering the OC protection mechanism.

Recommended Solutions:

• Inspect and Shorten Motor Cables: Review the cable length and ensure it meets the manufacturer’s recommendations. If possible, shorten the cable length to reduce leakage current.
• Upgrade Cable Quality: Replace existing cables with higher-quality, appropriately rated ones to minimize leakage current issues.
• Tighten Cable Connections and Check for Damage: Thoroughly inspect all cable connections for tightness and integrity. Replace any damaged cables immediately.
• Monitor and Adjust Load Conditions: Keep track of load changes and adjust inverter settings accordingly to avoid excessive current surges.
• Inspect and Replace Drive Board/Module: If the issue persists despite the above measures, consider replacing the drive board or entire inverter module, as the internal circuitry may have been damaged.

By addressing these potential causes and implementing preventive maintenance practices, operators can significantly reduce the likelihood of OC alarms in their Zhongchen Inverter NZ200 series, ensuring the smooth and reliable operation of their industrial automation systems.

I. Analysis of INI Alarm Causes

1. Literal Interpretation of INI Alarm
   • In VFDs, the “INI” alarm likely indicates issues or errors encountered during the device’s initialization process. This can stem from various reasons, including improper parameter settings, hardware failures, firmware issues, or external device connection errors.
   • For VFDs like the NZ200T, which employs open-loop vector control, the “INI” alarm may signify the VFD’s failure to correctly complete its initialization process upon startup or reset. This could result from unsatisfied specific hardware or software conditions, leading to the interruption or failure of the initialization process.
2. Initial Position Error
   • The INI alarm in ZONCN VFDs typically indicates an initial position error. This may occur when the VFD fails to accurately detect the motor’s initial position at startup, preventing the control program from executing subsequent commands accurately. Initial position errors can arise from various factors, including incorrect motor parameter settings, current circuit faults, or signal transmission issues.
3. Improper Motor Parameter Settings
   • The NZ200T VFD requires accurate setting of various motor parameters, such as rated voltage, rated current, and power factor. Inaccurate settings, particularly a low rated current setting, will prevent the VFD from effectively adjusting to the motor’s actual load conditions, thereby triggering the INI alarm.
4. Current Matching Fault or Signal Transmission Issue
   • The NZ200T VFD operates in open-loop vector control mode, necessitating precise current detection for accurate model analysis. Damage to the current transformer or issues with the signal transmission lines, such as poor contact or signal interference, will affect the VFD’s accurate determination of the motor’s position, subsequently triggering the INI alarm.
5. Control Mode Mismatch
   • The NZ200T VFD is designed for use with synchronous motors. When connected to a standard asynchronous motor or if the control mode is not correctly set, the INI alarm may also appear. This is because different types of motors exhibit distinct operational characteristics and control requirements, necessitating corresponding adjustments to the VFD’s control strategy based on the motor type.

II. Solutions

1. Recheck Motor Parameters
   • Firstly, carefully verify the settings of all motor parameters, ensuring consistency with the data on the motor’s nameplate. Pay particular attention to key parameters such as rated current, which should be set according to the motor’s actual specifications to avoid INI alarms caused by improper parameter settings.
2. Inspect Current Transformer and Signal Transmission Lines
   • Check the current transformer for damage or looseness, and replace it if necessary. Simultaneously, inspect the connection of the current transformer’s signal transmission lines to ensure good contact and absence of signal interference. If aged or damaged lines are found, promptly replace them with new ones.
3. Adjust Control Mode
   • If the NZ200T VFD is connected to a standard asynchronous motor, adjust the control mode to V/F control mode. Refer to the VFD user manual for specific setting methods: set parameter P0-02 to 2 and P1-04 to 50 (V/F control). This allows the VFD to directly control the standard asynchronous motor by adjusting the frequency for speed regulation, without altering other parameters. Additionally, ensure that the VFD’s software version matches the motor type to avoid control issues due to software incompatibility.
4. Seek Professional Technical Support
   • If the above methods fail to resolve the INI alarm issue, it is recommended to contact longi’s technical support team or professional maintenance personnel for fault troubleshooting and repair. When contacting technical support, provide a detailed description of the equipment’s operating environment, operation process, and alarm phenomena to enable technicians to quickly identify the problem and provide solutions.

In summary, the causes of INI alarms in the NZ200T VFD are diverse and require case-by-case investigation and resolution. By reasonably setting parameters, regularly inspecting equipment status, and seeking professional technical support, the incidence of INI alarms can be effectively reduced, ensuring stable equipment operation.

I. Operation Panel Functions and Instructions

The operation panel of the Great Inverter VC8000 series serves as the primary interface for user interaction with the inverter. It mainly consists of a display area and functional keys. Below are the main functions of the operation panel:

1. Display Area
   • Digital Display: Shows the current working status, frequency setting value, operating parameters, and other information of the inverter.
   • Function Indicators:
     • FWD/REV: Forward/Reverse indicator. Light off indicates forward operation, light on indicates reverse operation.
     • RUN: Running indicator. Light off indicates stop, light on indicates running.
     • LOCAL/REMOT: Command source indicator. Light off indicates panel control, light on indicates terminal control, flashing indicates communication control.
     • TUNE/TC: Tuning/Torque Control/Fault indicator. Light off indicates normal operation, light on indicates torque control, slow flashing indicates tuning status, fast flashing indicates fault status.
2. Functional Keys
   • PRG/Programming: Enters or exits the menu for parameter modification.
   • ENTER/Confirm: Enters the menu, confirms parameter settings.
   • ▲ Increment: Increments data or function codes.
   • ▼ Decrement: Decrements data or function codes.
   • < Shift: Selects parameter modification digits and display content.
   • RUN/Run: Starts the inverter.
   • STOP/RESET: Stops or resets the inverter.
   • MF/Multi-Function: Multi-function selection key, with specific functions determined by the P7-01 function code.

II. Wiring Instructions for Terminal Start/Stop and Potentiometer Debugging

1. Wiring Instructions
   • Start/Stop Control Wiring:
     • Start Terminal: Typically, the start signal is connected to DI1 (or another specified digital input terminal) and configured as a forward running command (e.g., P4-00=1).
     • Stop Terminal: Connected to DI2 (or another specified digital input terminal) and configured as a fault reset or stop command (e.g., P4-01=9).
   • Potentiometer Debugging Wiring:
     • If an external potentiometer is used for frequency adjustment, connect +10V and GND to the power terminals of the potentiometer, and connect the center tap to AI1 (analog input 1).
2. Parameter Settings
   • To meet control requirements, set the following parameters:
     • P4-00: Set DI1 as the forward running command (e.g., set to 1).
     • P4-01: Set DI2 function according to needs, typically as fault reset or stop command.
     • AI1-related Parameters: Ensure AI1 is configured to receive frequency settings (e.g., set P0-03 to AI1).
     • Other Necessary Parameters: Set relevant parameters in P0 group (basic function parameters), P2 group (vector control parameters), etc., according to specific needs.

III. Fault Code Analysis and Solutions

When faults occur in the Gelite Inverter VC8000 series, fault codes prefixed with “ERR” will be displayed. Below are analyses and solutions for some common fault codes:

1. ERR01 – Inverter Unit Protection
   • Cause: May be due to inverter overheating, short circuit, or drive board failure.
   • Solution: Check if the inverter module is overheating, check for short circuits in the motor and cables, and if the problem persists, contact the manufacturer for repair.
2. ERR02/ERR03/ERR04 – Acceleration/Deceleration/Constant Speed Overcurrent
   • Cause: Excessive motor load, short acceleration time setting, output short circuit, etc.
   • Solution: Check the motor load, appropriately extend the acceleration time, and check for short circuits in the output circuit.
3. ERR05 – Constant Speed Overvoltage
   • Cause: Excessive power supply voltage, abnormal braking unit, etc.
   • Solution: Check the power supply voltage and confirm if the braking unit is working normally.
4. ERR08 – Control Power Fault
   • Cause: Abnormal control power, such as unstable voltage or power cut.
   • Solution: Check the control power supply voltage and ensure stable power supply.
5. ERR19 – Overload
   • Cause: Motor operating under overload for an extended period.
   • Solution: Reduce the motor load and check for abnormalities in the mechanical parts.

Note: The above are only analyses and solutions for some fault codes. During actual use, please refer to the specific fault code manual for operation. For faults that cannot be resolved, please promptly contact longi technical support.

Operation Panel Key Descriptions:

• PRGM/ESC: Program setting and exit key. PRGM is used to enter programming mode or set parameters, while ESC is used to exit the current setting or return to the previous menu.
• FUNCTION/DATA: Function selection and data key. FUNCTION is used to enter the function selection interface, and DATA is used to modify data values during parameter setting.
• FORWARD/REVERSE: Forward and reverse control key. Controls the forward or reverse rotation of the motor.
• JOG/>>: Jog and page turning key. JOG is used for jog control, and >> may be used for page turning or increasing parameter values (specific functions may vary depending on the model).
• RUN: Run key. Controls the startup of the VFD.
• STOP/RST: Stop and reset key. STOP is used to stop the VFD operation, and RST is used to reset the VFD and clear fault states.
• UP/DOWN: Up and down adjustment key. Used to increase or decrease values during parameter setting.

Terminal Start/Stop and Potentiometer Debugging Wiring Instructions:

Terminal Start/Stop:

• Parameter Setting: Ensure parameter F0.02 is set to 1, selecting terminal control mode.
• Wiring Instructions:
  • Connect the external start signal to the S1 terminal of the VFD.
  • Short-circuit the S1 terminal with the common terminal DCM to send a start signal, causing the VFD to begin operation.
  • Disconnect the short-circuit between S1 and DCM to send a stop signal, causing the VFD to stop operation.

Potentiometer Debugging:

• Parameter Setting: Ensure parameter F0.03 is set to 1, selecting external potentiometer speed adjustment mode.
• Wiring Instructions:
  • Connect the center tap (sliding contact) of the potentiometer to the AVI terminal of the VFD.
  • Connect the two ends of the potentiometer to the 10V (or similar positive power supply) and ACM (or similar common terminal) of the VFD, respectively.
  • Adjust the position of the potentiometer to change the voltage value of the AVI terminal, thereby controlling the output frequency of the VFD.

Fault Code Analysis and Solutions:

Fault Codes:

• E001: DC bus fault. Possible causes include abnormal input power, faulty bus capacitors, etc. Solution: Check if the power input is normal, inspect the bus capacitors for damage, and replace if necessary.
• E002: Acceleration overvoltage. Possible causes include excessively short acceleration time, sudden load changes, etc. Solution: Adjust the acceleration time and check for load stability.
• E003: Constant speed overvoltage. Similar to E002 but occurs during constant speed operation. Solution is the same.
• E004: Acceleration overcurrent. Possible causes include motor stall, excessive load, etc. Solution: Inspect the motor and load conditions, reduce the load, or optimize motor operating conditions.
• E005: Deceleration overcurrent. Possible causes include excessively short deceleration time, large load inertia, etc. Solution: Adjust the deceleration time and consider using a braking unit and braking resistor.

Please note that the above content is based on the information you provided. During actual operation, please refer to the VFD manual and related materials. If you have any questions, please contact Longi Electromechanical’s technical support or professional maintenance personnel promptly.

I. Procedure for Viewing and Modifying Function Codes on the T8 Series VFD Operator Panel

2. Starting the Operator Panel:
   • After powering on the VFD, press the power button (labeled “POWER” or similar symbol) on the operator panel to activate it.
3. Viewing and Modifying Function Codes:
   • Use the directional keys (↑↓←→) on the operator panel to select the desired function code for viewing or modification.
   • Press the “ENTER” key to enter edit mode, where you can input new parameter values using the numeric keys or view the current values.
   • After making changes, press “ENTER” again to confirm the modifications and exit edit mode.
   • Note: Access to some advanced function codes may require entering a password.
4. Parameter Structure and Status Parameter Review and Setting:
   • VFD parameters are typically grouped, such as motor parameters (P0 group), control parameters (P1 group), and protection parameters (P2 group).
   • To review specific parameters, refer to the parameter table in the manual to find the corresponding parameter number (e.g., P0.01, P1.05) and parameter description.
   • Status parameters (e.g., current frequency, current, voltage) can be directly viewed through specific function codes, providing real-time insights into the VFD’s operating status.

II. Explanation of Control Circuit Terminals and Wiring Methods for the T8 VFD

1. Explanation of Control Circuit Terminals:
   • FWD/REV (Forward/Reverse Control Terminals): Connect to external buttons or switches to control the VFD’s forward and reverse rotation.
   • RUN/STOP (Run/Stop Control Terminals): Control the VFD’s start and stop functions.
   • AI1/AI2 (Analog Input Terminals): Receive analog signals from potentiometers, PLCs, etc., for frequency adjustment.
   • FAULT (Fault Output Terminal): Outputs a signal to external devices when the VFD detects a fault.
   • RUN (Run Indicator Light): Illuminates when the VFD is in the running state.
2. Wiring Methods for the Control Circuit:
   • Connect the corresponding control signal wires to the designated terminals based on actual control requirements.
   • When using terminal start and potentiometer adjustment, ensure:
     • Analog input parameters are set correctly, including input type (voltage/current) and range.
     • The frequency setting method is selected as “Analog Input.”
     • Forward/reverse control parameters are set according to actual needs.

III. Explanation and Resolution of VFD Fault Codes

Based on the specific instructions in the “Theta VFD T8 Series Manual,” here are some common fault codes and their resolutions:

• OC (Overcurrent Fault): Check if the motor and load are excessively large, optimize motor parameters or load distribution; inspect motor insulation for integrity.
• OV (Overvoltage Fault): Verify input voltage stability, use a voltage stabilizer if necessary; inspect power lines for abnormalities.
• UV (Undervoltage Fault): Check the input power source for normalcy, troubleshoot power supply issues; inspect power lines for poor contact.
• OH (Overheat Fault): Improve ventilation conditions, reduce ambient temperature; check for blocked heat sinks and clean dust inside the VFD.
• EF (External Fault): Verify the normalcy of the external fault signal source; inspect the wiring of external devices for secure connections.

Please note that this content is a summary of the user guide based on select sections of the “Theta VFD T8 Series Manual.” Always refer to the original manual for detailed steps, precautions, and any additional information. For questions or further assistance, consult the manual or contact longi VFD’s technical support department.