The motor arrived at our facility with the message: shaft blocked no rotation possible.
At first, we suspected a bearing failure or seized mechanics, but once the motor was opened, the true extent of the damage became apparent:
The brake was completely destroyed and stuck solid. The friction lining had turned into fine dust and spread throughout the entire interior of the motor.

The fine brake dust had penetrated deep into the bearings, damaging the raceways and leading to the failure of the encoder, as the optical reading was disrupted.
A typical case that most would consider an economic total loss but for us, it was a repairable special case.

After complete disassembly, the motor was chemically cleaned, the old paint removed, and all components carefully inspected.
The brake was replaced, the encoder repaired and recalibrated, and the bearings, seals, and a damaged connector were renewed.
After reassembly, the motor was tested on our Yaskawa SGDH-05DE test stand:

• Functional test in no-load and load operation
• Measurement of torque, current, and encoder signals
• Insulation and high-voltage testing
• Endurance run at 1500 rpm over several hours

After testing, the motor once again ran smoothly, precisely, and stably.
To finish the process, it received a new industrial coating and protective sealing.

The customer benefited from a significant cost saving compared to a new motor and from extended service life due to the preventive overhaul.

Causes of Encoder or Motor Failures

• Penetration of moisture or oil mist
• Temperature fluctuations and condensation
• Mechanical vibrations and shocks
• Aged seals and contamination
• Cable breaks and loose connections
• Long standstill periods causing brake adhesion
• Dust or metallic particles inside the housing

Failures often develop gradually – beginning with irregular motion, sporadic encoder errors, or position deviations until the motor ultimately fails completely.

Preventive Tips for Customers

• Keep the environment clean and dry
• Check brake and bearings for noise or play
• Inspect cables for bends or cracks
• Avoid strong temperature fluctuations
• Plan a preventive overhaul every 3–5 years
• Use only original spare parts and tested connectors

Information about the mentioned Servopack and Servomotor:

• Yaskawa SGMGH-05DCA6H AC Servo Motor
• Encoder Yaskawa UTSIH-B17CK
• Ogura-Bremse SBR-112V-45B (24 VDC)
• Yaskawa Servopack SGDH-05DE

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 & Compatible Devices

The SGMGH-05DCA6H is part of Yaskawa’s Sigma II servo family, designed for precise motion in CNC machines, robots, and automation lines.
It operates reliably in industrial environments when protected from oil, moisture, and temperature fluctuations.

Compatible Drives: SGDH-05DE, SGDH-05AE, SGDH-05ADA
Applications: Axis drives, tool changers, feed units, robot motion

Function Description

The SGMGH-05DCA6H is a 450 W three-phase AC servo motor with high torque stability and a 17-bit absolute encoder (UTSIH-B17CK).
It provides smooth, accurate operation and is widely used for motion control tasks requiring precision and repeatability.
The optional brake SBR-112V-45B ensures secure holding during power-off states.

Alarm Messages & Troubleshooting

Components