Applicable Systems
Street Crane Overhead Crane
Symptoms
The Street Crane system displays alarm ST004, indicating hoist motor overheat. The hoist motor temperature has exceeded the safe operating limit, triggering thermal protection and stopping the hoist.
Possible Causes
- Motor cooling fan is blocked or failed, reducing heat dissipation from the motor frame
- Hoist is being operated at a duty cycle exceeding the motor's thermal rating, causing heat buildup
- Motor bearing is worn, increasing friction and generating excess heat at the bearing housing
Troubleshooting Steps
- Step 1: Check the motor cooling fan operation and the airflow at the motor intake and exhaust
Fan is running and airflow is unobstructed at both the intake and exhaust vents - Step 2: Review the hoist duty cycle against the motor thermal class and the rated duty cycle
Operating duty cycle is within the motor's rated thermal capacity for the current ambient temperature - Step 3: Check the motor bearing temperature and listen for bearing noise during operation
Bearing temperature is below 80C and no grinding or rumbling noise is heard
How to Reset
To reset: 1) Replace the cooling fan or clear blockages. 2. Reduce the duty cycle. 3. Replace worn bearings. 4. Allow the motor to cool below 60C. 5. Press RESET. 6. Verify motor temperature is stable during operation.
Source: Street Crane Manual, Street Crane Company Limited
Category: Crane