08.07.2025 by Viktor Siebert
A Remarkable Case Involving the Yaskawa AC Servo Motor SGMGH-05K5A-SE19
Approximately fifteen years ago, a joint venture between Siemens and Yaskawa brought a new series of controllers, servopacks, and motors to the market. Several machine manufacturers, including Star and Matsuura, integrated these components into their machines. However, the partnership was dissolved shortly after its launch. Since then, the procurement of spare parts for these systems has become increasingly difficult.
One of the most affected models is the Yaskawa AC Servo Motor SGMGH-05K5A-SE19, which is operated together with the SGDK-050505AEA-V servopack. This motor type is a direct product of the former Siemens-Yaskawa cooperation. We are highly familiar with this model, having successfully repaired over forty units to date.
One of our clients from Italy faced significant challenges sourcing functional replacements for these motors. He operates a large number of machines equipped with this model, mainly from Star and Matsuura. After exhausting all his spare units, he tried sourcing used motors online. Unfortunately, most of these were either fake or already defective. After three failed purchases, he gave up and searched for alternatives.
He discovered us through an article we had published a few months earlier, in which we shared our repair experiences with this specific model. We regularly publish similar stories from our workshop to inform customers about known issues and repair possibilities for specific units or entire product series.
In this particular case, the issue – as is often the case was a faulty encoder. The brake was still in good condition and did not require replacement. We replaced the encoder with a new unit, which we programmed specifically for this motor type. This is a critical step, as the motor will not function properly without correctly matched encoder programming.
Our repair process starts with a complete visual inspection. We then perform electrical tests to verify insulation, windings, and feedback signals. The motor is fully disassembled, cleaned, and all components are measured. Worn bearings are replaced, the shaft is checked and, if needed, reworked. The encoder is installed and programmed, and the unit is then tested under load on a dedicated test rig. Only after passing the full functional test is the motor released for return.
The Italian customer was so satisfied that he sent us all of his remaining motors for refurbishment. The volume of this order pushed our resources to the limit, as we continue to handle regular repairs in parallel. Normally, such a project would take several months. Fortunately, the customer was relaxed and didn’t need everything at once. For him, it was more important to finally have a reliable partner. He is now also sending in the associated SGDK-050505AEA-V servopacks for overhaul but that’s a story for another time.
Standard Repair Procedure for Servo Motors (Yaskawa SGMGH-05K5A-SE19)
Our structured repair process ensures that every motor we refurbish meets or exceeds original specifications. All work is performed in-house by experienced specialists using professional-grade equipment.
1. Incoming inspection and documentation
Upon arrival, the motor is visually inspected, photographed, and documented. We record all labels, serial numbers, and mechanical details and compare them to the OEM specification.
2. Initial electrical testing
Before disassembly, we conduct a preliminary electrical analysis:
- Winding resistance
- Insulation values
- PE connection
- Feedback signal integrity
- Brake voltage and response
3. Visual inspection of mechanical and thermal damage
We check for shaft wear, damage to the flange, seal failures, corrosion, and heat marks which may indicate deeper issues.
4. Disassembly and cleaning
The motor is fully disassembled and all parts are carefully cleaned, including ultrasonic bath treatment if necessary. Components are thermally dried and conditioned.
5. Fault analysis and replacement of defective parts
We perform a detailed failure analysis. Components such as defective encoders, bearings, or seals are replaced with new ones.
In this case (SGMGH-05K5A-SE19), the original absolute encoder UTSAH-B17BE was replaced and reprogrammed to match the motor type exactly.
6. Bearing replacement and reassembly
We use only high-quality bearings (e.g., SKF or NSK). The shaft is measured and reconditioned if needed. Final reassembly follows original manufacturing standards.
7. Load testing on original drive unit
After assembly, the motor is tested under load using the corresponding drive (SGDK-050505AEA-V). We verify:
- Encoder feedback (including Z-pulse)
- Torque characteristics
- Brake function
- Idle current and runout
- Temperature behavior
8. Final inspection and test report
Once all tests are passed, the motor is sealed and shipped with a detailed test report. On request, we provide a comprehensive repair summary.
9. Return shipment
The motor is carefully packed for transport. Express delivery and advance exchange options are available upon request.
Information about the mentioned Servopack and Servomotor:
More information about our Yaskawa repairs can be found here.
📞 Feel free to contact us if you have any questions regarding your Yaskawa drive technology. Our experienced team is always ready to assist you.
Device Specifications (SGMGH-05K5A-SE19)
| Parameter | Value |
|---|
| Motor Model | SGMGH-05K5A-SE19 |
| Series | Yaskawa Sigma-II |
| Voltage | 200 V AC |
| Rated Power | 450 W |
| Rated Speed | 1500 rpm |
| Rated Torque | 2.84 Nm |
| Peak Torque | 8.92 Nm |
| Rated Current | 1.9 A (RMS) |
| Max Current | 5.5 A (RMS) |
| Protection Class | IP67 (except shaft opening) |
| Encoder Type | Absolute Encoder UTSAH-B17BE (17-bit) |
| Brake | Holding Brake MCNB 40-01, DC 90V |
| Cooling | Self-cooled |
| Insulation Class | Class F |
| Mounting Type | Flange mount |
| Weight | approx. 5.5 kg |
Application Environment
- Used in: CNC machines, automation lines
- Machine Brands: Star, Matsuura
- Partner Device: Yaskawa Servopack SGDK-050505AEA-V
- Typical Issues: Encoder failure, obsolete spare parts
Key Components
| Component | Type / Description | Function |
|---|
| Encoder | UTSAH-B17BE (17-bit absolute) | High-resolution position feedback |
| Brake | MCNB 40-01, DC 90V | Holding function during machine stop |
| Drive | SGDK-050505AEA-V (Yaskawa Servopack) | Power and control for the motor |
| Mounting | Flange type | Direct integration into machine frame |
| Shaft | Tapered with key and thread | Secure mechanical power transmission |
