Initial situation and fault description.

The Yaskawa converter CIMR-MRXN2022 Spec 20225A was sent in by the customer with the fault description “no function, no display, no startup”. According to the customer, the failure occurred suddenly. The machine had been operating without any noticeable abnormalities or warning messages for a long period of time beforehand. There was no external event such as a power supply disturbance or a short circuit within the machine. The failure occurred during operation and led to an immediate machine shutdown.

Incoming inspection and initial diagnosis

After opening the unit, a clear damage pattern was already visible during the visual inspection. The power section showed thermal traces, particularly in the area of the power semiconductors. Electrical pre-testing confirmed an internal short circuit within the power stage. The unit was no longer able to power on, and the internal protection logic prevented any startup attempt. Supplying the control electronics externally was also no longer possible.

Analysis of the root cause

During further disassembly, the actual root cause became evident. The internal cooling fan was completely blocked. Heavy contamination caused by dust, oil mist, and deposits had led to the fan no longer rotating. As a result, insufficient cooling of the power components occurred over an extended period of time.

This thermal stress gradually caused aging of critical components. Optoelectronic components lost signal stability, electrolytic capacitors showed significantly reduced capacitance values and increased ESR values. Consequently, the control of the transistor modules became unbalanced. One power channel was overloaded and destroyed, and the transistor module exhibited a complete short circuit. This process often remains unnoticed because protective mechanisms only intervene when the damage is already advanced.

Repair process and refurbishment

As part of the repair, the converter was completely disassembled and thoroughly cleaned. All thermally stressed assemblies were inspected and refurbished. The power stage was overhauled, damaged power semiconductors were replaced, and the associated control circuitry was rebuilt. In addition, age-critical components in the vicinity of the power stage were replaced preventively to ensure long-term stability.

Special attention was given to the cooling system. The fan was replaced and the internal airflow paths were cleaned. This is the only way to ensure reliable heat dissipation and to prevent renewed thermal overload. After completion of the repair, the unit underwent a multi-stage functional test under load conditions, including temperature monitoring and extended endurance testing.

Importance of preventive maintenance

This repair case clearly demonstrates how critical proper cooling is for high-power converters. A blocked fan does not cause immediate failure but leads to gradual damage of the electronics. Regular maintenance according to manufacturer specifications, especially periodic replacement of cooling fans and cleaning of cooling channels, can reliably prevent such total failures. Preventive maintenance significantly extends service life and reduces unplanned machine downtime.

Conclusion

The Yaskawa CIMR-MRXN2022 was fully restored through professional refurbishment. The damage was age-related and was promoted by a failed cooling fan. This case highlights the importance of regular maintenance and shows that timely refurbishment is far more economical than replacing complete power units.

Further information such as price and delivery time for:
Yaskawa Converter CIMR-MRXN2022 (Spec 20225A)

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Technical Information Yaskawa Converter CIMR-MRXN2022

Technical specifications

Typical applications

Typical alarms and fault causes

Main assemblies