03.07.2025 by Viktor Siebert
Signs That Your Spindle Drive Needs Maintenance. Case Mitsubishi MDS-B-SP-260 Spindledrive
Loss of Power: “I can no longer machine heavy parts.”
A long-time customer contacted us with a clear issue: his Mitsubishi MDS-B-SP-260 spindle drive had lost performance over the years. At first, the problem was subtle. But eventually, the machine was no longer able to process heavier workpieces with the usual power and precision—a clear indication that the drive was no longer delivering full output.
First Countermeasures: Program adjustments and reduced feeds
The customer initially tried to compensate by adjusting the machining programs. Feeds were lowered, cycle times were extended, and cutting parameters were softened. This worked for a while—but the performance gap kept growing.
Red Flag: “Overload” errors occurring more and more frequently
Soon, the “Overload” alarm became a daily issue—appearing multiple times per shift. This kind of error typically indicates:
- Deterioration of power electronics
- Overload of aging internal components
- Thermal buildup or fan failure
- Capacitor degradation
In many cases, it also reflects unstable current regulation—an early warning sign that preventive action is needed before major damage occurs.
Smart Decision: Repair before total failure
Fortunately, the customer made the right decision and contacted us before things got worse. He requested a professional overhaul before the spindle drive caused a full production stop or damaged surrounding equipment like the motor or power supply unit.
Our Preventive Repair Process: Standardized, tested, documented
We’ve developed a structured and proven repair process for MDS-B-SP-260 drives, based on many years of field experience:
Visual Inspection & Analysis
- Check for visible damage, thermal wear, and signs of previous repairs
- Review the fault history (if available)
- Inspect fan function, terminal connections, and interface ports
Electronic Diagnostics & Component Replacement
- Replace all known wear-prone components—regardless of their current status
- Exchange of capacitors, relays, IGBT modules, gate drivers, and opto-couplers
- Cleaning and resealing of heat-conducting surfaces
- Fan replacement or overhaul
Load Testing on Test Bench
- Functional testing under 200 V / 3-phase simulated load
- Simulated real-world operation with overload pulses
- Temperature, voltage, and current monitored throughout
Final Inspection & Documentation
- Isolation resistance check, ripple current test, and leak current measurement
- Full documentation of replaced parts and performed actions
- Drive serial number logged for traceability
Our Tip: Don’t wait for the next error
Spindle drives like the MDS-B-SP-260 are the heart of your CNC machine. Declining performance or recurring errors are not minor annoyances—they’re your system’s early warning signals. Acting quickly can save downtime, reduce costs, and prevent catastrophic failures.
To mentioned Mitsubishi Drive: Mitsubishi MDS-B-SP-260 Spindle Drive Unit
More details about our Mitsubishi repair services can be found here:
Mitsubishi drive Repair by Industrypart
📞 Feel free to contact us with any questions about your Yaskawa drive technology.
Our expert team is happy to help!
Technical Specifications – Mitsubishi MDS-B-SP-260
Parameter | Specification |
---|
Model | MDS-B-SP-260 |
Drive Type | AC Spindle Drive Unit |
Rated Output Power | 26 kW |
Input Voltage | DC 270–311 V (from power supply unit) |
Input Current | 115 A DC |
Input AC (for fan etc.) | 0.2 A, 1-phase, 200–230 V, 50/60 Hz |
Output Current | 97 A |
Output Voltage | 3-phase, 200 V, 0–833 Hz |
Cooling | Forced air cooling (internal fan) |
Installation | Panel mounting in control cabinet |
Dimensions (H×W×D) | 380 × 150 × 300 mm |
Weight | 10.0 kg |
Manual Reference | BNP-B3759B (Specification Manual) |
Compatible Power Supply | MDS-B-CV-260 (DC power supply unit, 260 V, 97 A compatible) |
Environment (Operation) | 0–55 °C, 90% RH or less, no condensation, indoor use only |
Environment (Storage) | −15 to +70 °C, dry, dust-free storage |
Alarm and Warning Messages – Mitsubishi MDS-B-SP-260
Alarm No. | Abbr. | Name | Description |
---|
12 | ME1 | Memory error 1 | A checksum or RAM error occurred in the spindle drive control card ROM |
13 | SWE | Software process error | Software process did not finish within the set time |
17 | ADE | AD error | The AD converter did not function correctly during initialization |
21 | NS2 | No signal (spindle encoder) | No signal input from spindle encoder or abnormal signal level |
23 | OSE | Excessive speed deflection | Speed command and actual speed deviation exceeded specified limits |
31 | OS | Overspeed | Motor speed exceeded 115% of the maximum set speed |
32 | PMOC | Power module overcurrent | Current exceeding the set value flowed into the IPM of the drive |
34 | DP | CRC error | CRC error occurred in communication data from the NC |
35 | DE | Data error | NC movement command exceeded limit during position control |
36 | TE | Transmission error | Periodic data transmission from NC was interrupted |
37 | PE | Parameter error | A parameter value exceeding the tolerable range was set |
38 | TP1 | Protocol error 1 | Protocol error in NC communication (frame level) |
39 | TP2 | Protocol error 2 | Protocol error in NC communication (information level) |
40 | KE1 | TK unit change error | Changeover signal procedure was incorrect using the TK unit |
41 | KE2 | TK unit communication error | Communication with TK unit was incorrect |
44 | CAXE | C-axis changeover alarm | Coil changeover alarm when using H coil for C-axis control |
46 | OHM | Motor overheat | Overload or cooling blower stop caused thermal protection to activate |
50 | OL | Overload | Motor current exceeded the set overload time constant |
52 | OD | Excessive error | Position tracking error exceeded specified limits in the loop control |
5C | ORFE | Orientation feedback error | Orientation pulse value was outside the set range at orientation complete |
60–7F | – | – | Refer to power supply section for related alarms |
82 | NSP | Power supply no signal | Breakage or misconnection of cable from power supply detected |
E1 | WOL | Overload warning | Motor current exceeded 80% of detection time constant |
E7 | NCE | NC emergency stop | Emergency stop signal received from the CNC |