oH1 Overheat (Heatsink) fault in delta drive

oH1 Overheat (Heatsink) fault in delta drive troubleshooting

Description

oH1 indicates that the heat sink temperature sensor has detected a temperature exceeding the safe operating limit (usually 85°C to 90°C). This is a thermal protection mechanism to prevent the IGBT power modules from melting or exploding.

Causes

1. Fan Failure: The cooling fans on the bottom or top of the drive are broken, jammed with dust, or running slowly.
2. Clogged Vents: The heat sink fins are clogged with cotton, dust, oil, or debris, preventing airflow.
3. High Ambient Temperature: The electrical panel is too hot (summer heat, no panel AC) or the drive is installed in direct sunlight.
4. Improper Mounting: No clearance space left above/below the drive for air circulation.

Solution

Cooling system maintenance:
1. Clean the Drive: Use compressed air to blow out dust from the heat sink fans and ventilation slots.
2. Check Fans: Visually inspect if the cooling fans are spinning. If not, replace them. Delta fans are usually easy to swap.
3. Panel Cooling: Ensure the cabinet has ventilation fans or air conditioning. Maintain ambient temp below 40°C-50°C.
4. Carrier Frequency: Lower the Carrier Frequency (Parameter 02-03 or similar). High carrier frequency (e.g., 15kHz) makes the motor quiet but generates significantly more heat in the drive. Dropping it to 4-6kHz reduces drive temp drastically.