1. Frequency Converter Overcurrent Faults

1.1 Overcurrent during Acceleration (E.oC1)

Causes:

• Excessive load inertia combined with too short acceleration time, leading to instantaneous overcurrent at startup.
• Motor faults, such as winding short circuits or grounding, causing abnormal current.
• Short circuit on the converter output side due to damaged cables or improper connections.
• Improper parameter settings, such as excessively high torque boost, resulting in excessive starting current surge.

Solutions:

• Extend the acceleration time by adjusting parameters like F01.22 (Acceleration Time 1) to ensure smooth motor startup.
• Inspect the motor using professional tools to measure winding insulation resistance and DC resistance; repair or replace the motor if damaged.
• Check the converter output wiring for damage, aging, or loose terminals, ensuring correct and short-free connections.
• Adjust the torque boost value (e.g., F04.01 Torque Boost) to avoid excessive current surge.

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1.2 Overcurrent during Deceleration (E.oC2)

Causes:

• Too short deceleration time, leading to unabsorbed regenerative energy and increased DC bus voltage.
• High load inertia causing excessive current during deceleration due to motor inertia.
• Incorrect brake resistor selection or faulty brake unit, failing to dissipate regenerative energy effectively.

Solutions:

• Lengthen the deceleration time by modifying parameters such as F01.23 (Deceleration Time 1) for smooth deceleration.
• For high-inertia loads, install a brake resistor or a higher-power brake unit (e.g., a 75Ω, 780W resistor for a 7.5kW motor in a 380V system).
• Check the brake resistor and unit for damage or malfunction, replacing faulty components as needed.

1.3 Overcurrent during Constant Speed (E.oC3)

Causes:

• Sudden load increase (e.g., mechanical jamming or abrupt load changes) leading to excessive motor current.
• Mismatch between motor and converter ratings, causing converter overload.
• Converter internal faults, such as damaged power modules or faulty current detection circuits.

Solutions:

• Inspect the mechanical load for jamming or abnormal operation and resolve accordingly.
• Verify motor-converter compatibility, ensuring the motor’s rated current is within the converter’s capacity.
• Contact professional technicians to check power modules and current detection circuits, replacing damaged parts.

2. Overvoltage Faults

2.1 Overvoltage during Acceleration (E.ou1)

Causes:

• Short acceleration time causing rapid speed rise and unabsorbed regenerative energy, increasing DC bus voltage.
• Excessive input voltage beyond the converter’s allowable range.
• Faulty brake unit or unconnected brake resistor, failing to absorb regenerative energy.

Solutions:

• Extend acceleration time (e.g., F01.22) to ensure gradual speed increase.
• Monitor input voltage to ensure it stays within the converter’s allowable 波动 range (e.g., -15%~10% for T3 models).
• Check the brake unit and resistor for proper connection and functionality, repairing or replacing as necessary.

2.2 Overvoltage during Deceleration (E.ou2)

Causes:

• Short deceleration time generating excessive regenerative energy.
• High load inertia leading to excessive energy feedback during deceleration.
• Incorrect brake resistor or faulty brake unit.

Solutions:

• Increase deceleration time (e.g., F01.23) for gradual speed reduction.
• Upgrade the brake resistor or unit for high-inertia loads and verify their specifications (e.g., resistance and power ratings).
• Inspect brake components for proper operation and replace faulty parts.

2.3 Overvoltage during Constant Speed (E.ou3)

Causes:

• Sudden grid voltage surges or fluctuations.
• Load in generating mode (e.g., potential loads descending), converting the motor into a generator and feeding back energy.
• Faulty voltage detection circuit in the converter, causing false overvoltage alarms.

Solutions:

• Install a voltage stabilizer to mitigate grid voltage fluctuations.
• Use brake resistors or energy feedback devices for generating loads to dissipate or 回馈 regenerative energy.
• Have professionals inspect and repair the voltage detection circuit.

3. Overload Faults

3.1 Motor Overload (E.oL1)

Causes:

• Prolonged heavy load operation due to mechanical jamming or transmission faults.
• Incorrect motor parameter settings (e.g., rated power/current mismatching the actual motor).
• Improper electronic thermal relay settings, failing to protect the motor in time.

Solutions:

• Inspect the mechanical load, clear jams, and repair transmission components to reduce load.
• Verify and correct motor parameters in the F02 group (Motor 1 Parameters).
• Adjust overload protection thresholds (e.g., F10.58 Motor Overload Start Threshold) according to the motor’s rated current.

3.2 Converter Overload 1 (E.oL2), Converter Overload 2 (E.oL3), Converter Overload 3 (E.oL4)

Causes:

• Excessive load exceeding the converter’s rated capacity.
• Incorrect converter sizing, with selected power lower than the actual load requirement.
• High ambient temperature impairing heat dissipation, leading to overheating.
• Lack of maintenance during prolonged continuous operation.

Solutions:

• Reduce load by troubleshooting equipment faults and optimizing operation.
• Re-select a converter with appropriate power ratings based on load requirements.
• Improve ventilation and clean heat sinks to ensure proper heat dissipation; add cooling fans if necessary.
• Perform regular maintenance, including dust cleaning and fan inspection.

4. Undervoltage Faults

4.1 Undervoltage during Operation (E.Lu)

Causes:

• Input power phase loss due to blown fuses or broken wires.
• Low input voltage below the converter’s allowable minimum.
• Faulty power detection circuit in the converter, causing false undervoltage alarms.
• Insufficient grid capacity leading to voltage sag during load startup.

Solutions:

• Check input power lines, replace fuses, and repair broken wires.
• Measure input voltage and address grid issues with the power provider if below standards.
• Have technicians repair or replace the power detection circuit.
• Install a voltage stabilizer for grids with insufficient capacity.

5. Overheating Faults

5.1 Rectifier Module Overheating (E.oH1)

Causes:

• Faulty cooling fan (damage or low speed) leading to poor heat dissipation.
• Dust accumulation on heat sinks, reducing cooling efficiency.
• Rectifier module faults (e.g., component aging or internal short circuits).
• Ambient temperature exceeding the converter’s operating range (-10℃~+50℃).

Solutions:

• Replace damaged fans and clean fan blades/dust from heat sinks to ensure proper airflow.
• Clean heat sinks thoroughly to restore heat dissipation performance.
• Test and replace faulty rectifier modules if aging or damaged.
• Improve ambient conditions, using air conditioning if necessary to maintain proper temperature.

5.2 IGBT Module Overheating (E.oH2)

Causes:

• Poor heat dissipation due to loose contact between the IGBT module and heat sink, or faulty fans.
• Excessive operating current due to prolonged overload.
• IGBT module aging or quality issues leading to increased heat generation.

Solutions:

• Ensure tight contact between the IGBT module and heat sink, reapplying thermal grease if needed.
• Clean cooling components and check for excessive load current; replace faulty IGBT modules.
• Monitor load conditions and address overload issues to prevent excessive current.

6. Phase Loss Faults

6.1 Input Phase Loss (E.iLF)

Causes:

• Open circuit in input power lines (e.g., blown fuses, broken wires).
• Poor contact in power switches, causing missing phase input.
• Faulty input phase-loss detection circuit in the converter.

Solutions:

• Inspect and repair input power lines, replacing fuses and fixing connections.
• Check and replace faulty power switches to ensure stable phase input.
• Repair or replace the input phase-loss detection circuit by professional technicians.

6.2 Output Phase Loss (E.oLF), U-Phase Loss (E.oLF1), V-Phase Loss (E.oLF2), W-Phase Loss (E.oLF3)

Causes:

• Open circuit in output cables due to damage or loose terminals.
• Faulty output drive circuit in the converter, preventing phase output.
• Motor winding open circuit (e.g., one-phase winding failure).

Solutions:

• Check output cables for damage and secure connections; repair or replace as needed.
• Test the converter’s output drive circuit and replace faulty components.
• Use professional tools to test motor windings and repair/replace the motor if faulty.

7. Communication Faults

7.1 Modbus Communication Fault (E.CE)

Causes:

• Poor communication cable connection (loose connectors, damaged cables).
• Mismatched communication parameters (baud rate, data format, address) between the converter and host.
• Damaged communication interface in the converter.
• Faults in host communication software or equipment.

Solutions:

• Inspect and secure communication cables, replacing damaged ones.
• Verify and match communication parameters in the F12 group (Communication Parameters), such as F12.02 (Baud Rate) and F12.03 (Data Format).
• Repair or replace the converter’s communication interface if damaged.
• Troubleshoot host-side issues, including software and hardware, to ensure compatibility.

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