Cause : Overcurrent trip during acceleration comes when the inverter output current reaches or exceeds the rated current during acceleration, the protection circuit is activated and the inverter output is shut off.

An EOC1 error in a Mitsubishi inverter indicates an overcurrent condition during acceleration. This means the motor connected to the inverter is drawing more current than the inverter is rated for during the startup phase. Here's a breakdown of the issue and some troubleshooting steps to help you resolve it:

Possible Causes of EOC1 Error:

• Rapid Acceleration: If the motor acceleration settings on the inverter are too aggressive, it can cause a surge in current exceeding the inverter's capacity during startup.
• Mechanical Obstruction: If the motor shaft is seized or has a mechanical blockage, it will require more current to overcome during startup, tripping the EOC1 fault.
• Loose Motor Connections: Poor connections between the motor and the inverter can cause excessive current draw due to arcing or resistance.
• Faulty Motor: In rare cases, an internal issue within the motor itself could lead to abnormally high current during acceleration.

Troubleshooting Steps:

1. Check Acceleration Settings:

• Refer to the Mitsubishi inverter's manual for your specific model. It should have instructions on how to access and adjust the motor acceleration settings.
• Try adjusting the acceleration ramp time to a slower rate. This will reduce the initial surge in current and might help prevent the EOC1 fault.

2. Inspect for Mechanical Obstructions:

• Turn off the inverter's power supply completely.
• Ensure the motor shaft turns freely by hand. Check for any mechanical binding or external factors that might be hindering motor rotation.

3. Verify Motor Connections:

• Turn off the inverter's power supply completely.
• Tighten all the motor cable connections at the inverter terminals and motor terminal box. Ensure all connections are clean and free of corrosion.