A customer brought us a Yaskawa SGMGS‑05A5W‑SE11 servo motor with a UTSAH‑B17BE encoder. His machine exhibited sporadic encoder faults. After each failure he had to realign the machine, and tools were damaged in the process. Because the motor was not available on the open market, he first replaced the matching Servopack SGDK‑050505AEA‑V without success. Only later did he learn that this was an old development from a joint venture between Yaskawa and Siemens, and the parts had been discontinued for years.

Why Conventional Parts Procurement Fails

The motor originates from a series that was produced only briefly. After the joint venture was dissolved, the components were withdrawn from the market. Machine operators tried to buy used motors through online platforms but often encountered counterfeit or already defective units. Even replacing the drive does not help when the real fault is inside the motor.

Our Solution, Repair Instead of Replacement

We have been familiar with this problem for years. In most cases the encoder is the weak point. Instead of risky used purchases, we have developed a structured repair process. We replace the defective encoder with a new original part and program it precisely for the motor. This preserves the original performance and avoids costly downtime.

How We Test and Repair

Our repair follows a clearly defined process that reliably restores each motor to its intended condition:

1. Incoming inspection and documentation
   When the motor arrives, it is carefully recorded, visually inspected and photographed. Serial numbers and labels are documented.
2. Preliminary electrical testing
   Before opening the motor, we check winding resistances, insulation values, PE connection, encoder connection and brake voltage.
3. Mechanical and thermal visual inspection
   We examine the shaft, bearing seats and flange for damage. Oil residues or corrosion indicate deeper issues.
4. Disassembly and cleaning
   The motor is completely disassembled. All parts are cleaned; the housing and windings are dried and thermally treated.
5. Fault analysis and replacement of defective components
   Defective bearings, encoders, seals or brakes are identified and replaced with new parts. The new encoder is installed and programmed.
6. Assembly and mounting
   We use brand‑name bearings, inspect the shaft and reassemble the motor precisely according to the manufacturer’s specifications.
7. Load testing on the test stand
   On an original servopack we check encoder feedback, torque build‑up, brake function, no‑load current and temperature behaviour.
8. Final inspection and quality report
   After passing all tests, the motor is sealed and delivered with a test report. On request the customer receives a detailed repair report.
9. Return shipment
   The motor is securely packaged for transport. Express delivery or advance exchange can be arranged.

Conclusion: Extending the Life of Discontinued Servo Motors

This story shows how important it is to have a reliable partner for the overhaul of discontinued components. With our specialised repairs, customers keep their machines productive and avoid the risks of buying defective used parts. We give Yaskawa/Siemens servos a second chance: with warranty, transparency and predictable availability.

Information about the mentioned Servopack and Servomotor:

• Yaskawa AC Servo Motor SGMGS-05A5W-SE11
• Encoder Yaskawa UTSAH-B17BE
• Servopack SGDK-050505AEA-V

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.

Technical Data of the AC Servo Motor (SGMGS‑05A5W‑SE11)

The following information comes from the motor’s nameplate and from manuals and data sheets for similar 0.45 kW Yaskawa servo motors.

Functional Description

The Yaskawa SGMGS‑05A5W‑SE11 is a three-phase permanent‑magnet synchronous servo motor. It belongs to the Σ‑V series (Sigma V) and delivers a rated torque of 2.86 N·m at 450 W output. The motor comprises a laminated stator with distributed windings, a high‑energy magnet rotor with low inertia, precision bearings and an integrated encoder (UTSAH‑B17BE) for position and speed feedback. This encoder provides incremental and absolute signals, enabling the controller to know the motor position at all times. Brakes (24 V DC or 90 V DC) and oil seals can be fitted to hold vertical axes when power is off or to protect the motor from oil or coolant ingress.

The servo amplifier SGDK‑050505AEA‑V forms the power and control unit. It converts the mains supply into a regulated voltage for the motor, controls current, torque, speed and position using vector current control and processes the feedback signals from the encoder. Motion commands can be issued via digital inputs from a PLC or CNC. The amplifier includes a regenerative braking stage that converts the braking energy into heat or passes it to an external brake resistor. Protective functions such as over‑current and over‑temperature protection, under‑voltage monitoring and communication fault diagnostics are built in. Together, motor and amplifier enable precise positioning and speed control for machine tools, printing presses, robots or packaging machines.

Alarm Messages and Troubleshooting

The table lists selected alarm messages from the inverter fault list. The CNC‑Code column is included where available; the Drive Code is critical. The Possible solution column gives troubleshooting hints based on general servo experience.