Applicable Systems
SMODEX 90t
Symptoms
The crane control panel displays E-601, indicating an overload protection system activation. The load cell has detected that the lifted load exceeds 100% of the rated capacity. All crane movements are disabled except lowering, and the alarm requires manual acknowledgment.
Possible Causes
- Actual load exceeds the crane rated capacity
- Load cell calibration drift causing false overload reading
- Load cell wiring fault or connector corrosion
- Snatch block or rigging configuration not accounted for in capacity calculation
Troubleshooting Steps
- Step 1: Verify the actual weight of the load against the crane load chart
If the load is genuinely too heavy, do not attempt to lift - use a larger crane or reconfigure rigging - Step 2: Check the load cell calibration with a certified test weight
Recalibrate if reading deviates from the reference by more than 1% - Step 3: Inspect the load cell cable and connector for damage or corrosion
Repair or replace damaged cable and apply dielectric grease to connectors - Step 4: Verify the rigging configuration and snatch block ratio
Update the capacity calculation if rigging has been modified
How to Reset
To reset E-601: 1) Lower the load to a safe position. 2) Resolve the overload condition - either reduce the load or recalibrate the sensor. 3) On the control panel, press and hold the Overload Reset button for 3 seconds. 4) The system performs a self-test. 5) If all checks pass, crane operation is restored.
Common Replacement Parts
- KC-90-001: Load cell, 90t capacity, compression type (Calibrate annually with certified test weights)
- KC-90-005: Load cell cable, 4-core shielded, 10m (Inspect for damage during daily checks)
- KC-90-010: Overload relay module, 24V DC (Verify trip point matches rated capacity)
Frequently Asked Questions
- Q: What should I do if the overload alarm activates during a lift?
Do NOT attempt to continue lifting. Carefully lower the load to the nearest safe landing area. Verify the actual weight against the load chart. If the weight is within capacity, suspect a sensor fault and do not resume until the load cell has been verified by a qualified technician.
- Q: How often should the load cell be calibrated?
Calibrate the load cell annually with certified test weights traceable to national standards. Additionally, verify calibration with a known weight quarterly. Any time the crane has been subjected to a shock load or the load cell has been replaced, perform a full calibration before returning to service.
Source: Konecranes SMODEX 90t Overhead Crane Manual, Edition 2019
Category: Crane