Initial situation

The delivered Yaskawa AC servo motor SGMDH-32A2A-YR33 showed sporadic encoder errors for an extended period. The customer had previously purchased a supposedly matching UTSAE-B17BB encoder and installed it himself. After installation the error became permanent and the motor was no longer operational. The motor was installed in a highly utilized robot which immediately affected production output. An express repair was required.

Incoming inspection and motor condition

The initial inspection showed an unusually contaminated motor interior. The OGURA RNB 1K-05A brake was completely worn out and the friction material had dispersed inside the motor. The dust spread across all internal assemblies including bearings, sealing areas and the encoder chamber. The encoder bearing showed clear signs of mechanical wear which caused unstable encoder rotation and signal drift. This led to sporadic failures.

The customer installed encoder was a used device from another motor type and programmed for a different resolution. It could not function on this motor type. Every start attempt resulted in immediate misalignment and feedback faults.

Systematic diagnosis

The motor was fully disassembled. All bearings showed wear beyond allowed limits. The seals were hardened due to contamination and thermal load. The encoder chamber was contaminated and the alignment surface showed minor wear. The windings were still within the thermal tolerance and showed no insulation defects.

The motor was tested on a Yaskawa SGDH-50AE Servopack. The feedback signals were unstable and out of tolerance which triggered repeated errors.

Repair process

The entire motor was cleaned using dry cleaning, wet ultrasonic cleaning and final solvent cleaning. All bearings and all seals were replaced. The brake OGURA RNB 1K-07 was replaced by a new original brake unit and adjusted to the correct holding torque.

The encoder was replaced by a newly programmed original UTSAE-B17BB encoder. The alignment was performed using a dedicated measurement system which included signal level analysis, zero pulse control and thermal drift monitoring.

The motor was reassembled, sealed and repainted.

Testing procedure

Testing was performed on an inhouse robot system to simulate real movements. Afterwards the motor was tested on a Yaskawa SGDH-50AE Servopack. The following parameters were evaluated:

• Feedback stability
• Temperature behavior
• Zero pulse stability
• Brake torque verification
• Vibration analysis
• Noise behavior
• Current consumption and torque buildup

All values were within specification.

Result and customer benefit

The motor was fully restored. The correct encoder guaranteed stable feedback again. The new brake ensured proper holding performance. The motor operated without errors or signal drift. The express repair enabled the customer to quickly resume robotic operations.

Note regarding dealers

An increasing number of dealers supply components without verifying technical compatibility. Encoders are sold used, incorrectly programmed or from different models. Each of these issues can cause severe downtime and additional repair costs. In this case a wrong encoder caused a production stop and unnecessary expenses.

Conclusion

The Yaskawa SGMDH-32A2A-YR33 was completely restored. The replacement of the brake, the full overhaul and the installation of a correctly programmed encoder ensured long term reliability. A professional repair prevents secondary damage and increases machine availability.

nformation about the mentioned Servopack and Servomotor:

• Yaskawa SGMDH-32A2A-YR33 AC Servo Motor
• Encoder Yaskawa UTSAE-B17BB
• Ogura-Bremse OGURA RNB 1K-07 90V
• Yaskawa Servopack SGDH-50AE

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 Specifications

Operating Environment and Compatible Devices

The SGMDH-32A2A-YR33 is typically used in:

• Robotic axes
• Pick and place systems
• Handling automation
• Gantry modules
• Machine tools with high cycle demand

Compatible Servopacks:

• SGDH-50AE
• SGDH-30AE
• SGDH Sigma II models of the same power class
(Selection depending on manufacturer specifications)

Functional Description

The motor operates as a high dynamic AC servo motor with magnetic rotor excitation and optical encoder feedback. The UTSAE B17BB encoder provides position, speed and reference pulse information. The OGURA RNB 1K-07 brake secures the axis during standstill conditions. Torque control, speed control and position control are executed inside the SGDH Servopack. The motor integrates thermal monitoring, vibration stability and precise feedback signals that are required for robotic applications.

Alarm Messages and Troubleshooting (SGDH Sigma II)

Extract based on the Sigma II alarm structure:

Components

Preventive Measures

• Inspect the brake every 12 to 24 months
• Do not install self sourced encoders
• Avoid opening the motor in dusty environments
• Replace seals and bearings at regular service intervals
• Check encoder feedback annually
• Maintain robotic axes with lubrication and alignment checks

Conclusion

Timely maintenance prevents downtime and protects production. After the complete overhaul the SGMDH 32A2A YR33 operates stable and reliable again.