22.01.2026 by Viktor Siebert
Repair of a Yaskawa CACR-120-PD1VDS01 Servopack with fan error
The servopack CACR-120-PD1VDS01 was received with Alarm 7 (fan error). According to the customer, the fault initially occurred sporadically and later led to a permanent axis shutdown. Externally, the unit showed no heavy contamination, which initially made the fault appear uncritical.
After opening the unit, the cooling fan was electrically tested. It was found that the fan itself was defective and no longer started properly. The defect was not mechanical but caused by an internal electrical failure of the fan.
During further analysis, it became apparent that the defective fan had caused a short circuit in the fan control circuit. This short circuit affected the electronics over an extended period of time. As a result of this continuous load, individual circuit sections on the power board were overloaded, particularly in the area responsible for fan supply and monitoring.
This type of failure progression is typical for unplanned fan failures. Initially, only the fan alarm is triggered. Cooling performance decreases without an immediate shutdown. During this phase, the servopack continues to operate with reduced thermal reserves. Components around the power stage and auxiliary power supply are continuously exposed to thermal and electrical stress. In this condition, gradual secondary damage occurs that is not immediately visible.
The faulty circuit was localized and repaired. The defective fan was replaced. Subsequently, the servopack was fully overhauled as a preventive measure. All components known to be affected by aging and thermal stress were inspected and replaced as a precaution. The objective was not only to eliminate the immediate fault but to restore long-term operational reliability.
After completion of the repair, the unit was tested on the test bench. Functional testing under load conditions was carried out, including temperature monitoring and continuous operation. The servopack then operated stably and within the specified limits.
This repair case clearly demonstrates that a fan alarm must not be treated as an isolated minor issue. A failed fan can lead to secondary damage to the power electronics within a short time. Regular cleaning, scheduled fan replacement, and timely overhaul reliably prevent such failure chains.
Information about the mentioned Servopack: Yaskawa Servopack CACR-120-PD1VDS01
Further details on our Yaskawa repairs can be found here: Yaskawa Sigma V Repair
📞 Feel free to contact us if you have any questions regarding your Yaskawa drive technology. Our team will be happy to assist you.
Technical Specifications
| Parameter | Value |
|---|
| Manufacturer | Yaskawa Electric Corporation |
| Device type | AC servopack |
| Model | CACR-120-PD1VDS01 |
| Protection class | IP10 |
| AC input | Single-phase 200–230 V AC |
| Line frequency | 50/60 Hz |
| Input current | 16 A |
| Motor output | Three-phase 0–230 V AC |
| Output current | 11.6 A |
| Output frequency | 0–400 Hz |
| Rated power | 1.5 kW |
| Cooling | Active fan cooling |
| Ambient temperature | 0–55 °C |
| Country of manufacture | Japan |
Installation Environment and Typical Applications
| Area | Description |
|---|
| CNC machines | Feed axes, positioning axes |
| Machine tools | Milling machines, lathes |
| Automation systems | Handling and feeding axes |
| Special machinery | Axis control with analog command signals |
The CACR series is frequently used in older CNC machines where analog servo control is applied. The device is comparable to later Yaskawa servopacks and shows functional similarities to the SGDV Sigma V series, particularly regarding protection functions and alarm behavior.
Functional Description
The servopack controls an AC servomotor via a pulse-width-modulated power stage. Speed and torque regulation is handled by internal control loops. Protection functions monitor current, voltage, temperature, and correct fan operation.
The cooling fan is a safety-relevant component. It ensures adequate cooling of the power electronics. If a malfunction is detected, the corresponding alarm code is triggered to prevent thermal damage.
Alarm Messages and Troubleshooting Yaskawa CACR-120-PD1VDS01
| Alarm code | Alarm name | Description | Typical cause | Recommended action |
|---|
| 1 | Overcurrent | Motor current exceeds permissible limit | Short circuit in motor, defective power electronics, incorrect wiring | Check motor cables and power stage |
| 2 | Overvoltage | DC bus voltage too high | Regenerative energy not dissipated, defective braking resistor | Check braking circuit and power supply |
| 3 | Undervoltage | Supply voltage too low | Mains voltage drop, contact problem | Check mains supply and connections |
| 4 | Overload | Thermal overload detected | Mechanical overload, incorrect parameter settings | Check mechanics and parameters |
| 5 | Encoder error | Feedback signal faulty | Encoder, cable, or connector defective | Check encoder circuit |
| 6 | Servo anomaly | Internal control fault | Unstable control loop, damaged power stage | Check electronics |
| 7 | Fan error | Fan not running or short circuit detected | Defective fan, damaged fan control circuit | Replace fan, check fan control |
| 8 | Overtemperature | Heatsink temperature too high | Fan failure, contaminated cooling surfaces | Restore cooling |
| 9 | Initialization error | Error during servopack startup | Internal hardware fault | Check electronics |
| A | CPU error | Internal control error | Logic fault, supply voltage problem | Repair required |
| b | Internal voltage error | Auxiliary voltage out of tolerance | Power supply section damaged | Check internal power supply |
| C | Communication error | Signal connection disturbed | Connector or cable issue | Check connections |
| d | System error | Internal protection triggered | Multiple faults, secondary damage | Comprehensive inspection required |
Main Components
| Assembly | Function | Inspection notes |
|---|
| Power board | Motor control | Check for thermal damage |
| Fan assembly | Cooling | Replace at regular intervals |
| Control board | Regulation and monitoring | Measure supply voltages |
| Heat sink | Heat dissipation | Check for contamination |
| Connectors | Signal and power paths | Check contact condition |
Preventive Measures for Operation
| Measure | Recommendation |
|---|
| Cleaning | Regularly, depending on environment |
| Fan replacement | Preventive, before failure |
| Visual inspection | Heat sinks, connectors, cables |
| Overhaul | Time-based instead of damage-based |
| Temperature monitoring | Use as early warning |
Conclusion
A fan failure is not a minor alarm. This repair case shows that a defective fan can lead to gradual overload of the power electronics. Preventive maintenance and timely overhaul reliably avoid unplanned downtime and secondary damage.