20.08.2025 by Viktor Siebert
Mitsubishi MDS-D-CV-110 Power Supply Unit, Ensuring Reliability through Repair and Prevention
A customer reported a failure with Alarm 1 (Power Supply Error). The CNC machine could no longer operate, production was stopped. Mitsubishi offered an exchange unit, but the cost was very high. Since the customer had already entrusted us with several repairs, he decided to send in this model as well, he had not known before that we could handle it.
Repair Process:
- Initial analysis with insulation and functional testing
- Thorough cleaning with special emulsion, followed by drying in a hot-air oven
- Preventive replacement of electrolytic capacitors, power transistors, optocouplers, and fans
- Testing of main capacitors for capacity and ESR values
- Documentation of every step using checklists
- Test run on a dedicated test bench under real load conditions
- Execution of thermal stress tests to ensure long-term stability
The repair was completed in less than 4 days. After reinstallation, the unit operated flawlessly.
Preventive Measures for the Customer
- Regular cleaning of cooling fins and fans
- Replace cooling fans every 3–5 years
- Inspect seals to prevent dust and oil ingress
- Perform insulation resistance measurements on motor cables
- Preventive overhaul of the power supply every 7–10 years
Conclusion
The Mitsubishi MDS-D-CV-110 is a robust and reliable power supply unit for CNC machines. With professional repair and preventive maintenance, its lifetime can be significantly extended. For customers, this means reduced downtime, lower costs, and increased machine availability.
To mentioned Mitsubishi Drive: Mitsubishi MDS-D-CV-110 Power Supply Unit
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Technical Summary of the Unit
| Parameter | Value |
|---|
| Type | MDS-D-CV-110 |
| Power | 7.5 kW |
| Input Voltage | 3-phase 200–230 V, 50/60 Hz |
| Input Current | 35 A |
| Output | 24 A, DC 283–311 V |
| Weight | approx. 8 kg |
| Manufacturer | Mitsubishi Electric Corporation |
| Year of Manufacture | 2010 |
Operating Environment & Compatible Devices
The power supply unit is part of the Mitsubishi MDS-D series and is used in CNC machines. It provides a stable DC supply for servo and spindle drives. Typical applications include machining centers such as milling and turning machines. It is compatible with servo drives of the MDS-D/DH series and corresponding spindle drives.
Functional Description
The MDS-D-CV-110 converts incoming AC voltage into a stable DC voltage for the connected drives. It integrates protective and monitoring functions such as overcurrent protection, voltage monitoring, thermal protection, and emergency stop integration. Without a functioning power supply, the entire CNC system is inoperable.
Alarm Messages and Troubleshooting
| Error Code | Cause | Solution |
|---|
| 61 | Power Module Overcurrent | Check load, reduce motor load, replace PSU if necessary |
| 62 | Input Frequency Error | Verify supply frequency, improve power quality |
| 66 | Process Error | Cycle fault, check environment |
| 67 | Phase Interruption | Check input voltage, inspect wiring |
| 68 | Watchdog Error | Inspect control system, replace PSU if necessary |
| 69 | Ground Fault | Check motor cable insulation, replace faulty cables |
| 6A | Contactor Welding | Check/replace external contactor |
| 6B | Rush Circuit Error | Inspect inrush current circuit, replace faulty parts |
| 6C | Main Circuit Error | Check main capacitors, replace PSU |
| 6D | Parameter Error | Reset parameters, verify communication |
| 6E | Memory / A/D Error | Check memory/A-D converter, replace PSU |
| 6F | No PSU Connected | Check cabling and communication |
| 70 | Emergency Stop Input Error | Inspect wiring of external emergency stop |
| 71 | Instantaneous Power Interruption | Verify mains supply stability |
| 72 | Fan Stop | Replace fan, check cooling system |
| 73 | Over-Regeneration >100% | Inspect resistor, wait before reset |
| 75 | Overvoltage | Inspect supply voltage and regeneration circuit |
| 77 | Overheating | Check cooling, ambient conditions, and load |
Components
| Type | Designation |
|---|
| Control Board | RK415D-21 or BN638A309G51 |
| Power Board | RM462C-2 or BC886A003G52 |
| Cooling Fan | Internal cooling unit |