The Hurco customer initially reported the error as a Y-axis problem, since the axis suddenly dropped down.
After several repetitions, the SGDH-15DE drive finally triggered the “Overload” alarm, and the motor could no longer be rotated by hand.

When the motor arrived, nothing unusual was visible from the outside.
However, inside the motor, the typical failure pattern became evident:
The brake was completely stuck, the friction lining had come loose, disintegrated, and spread throughout the entire motor interior.
Fine brake dust had contaminated the bearings, the encoder chamber, and the stator area.
A classic case usually caused by aging of the brake pad combined with oil mist contamination.

When the motor was opened, it became clear that it was mechanically blocked.
The ball bearings were destroyed, and the shaft rotation felt rough and uneven.
The UTSIH-B17CK encoder showed no apparent error in a static state but was heavily contaminated.

Together with the customer, the decision was made for a complete overhaul:

• Motor fully disassembled
• Chemical cleaning of all components
• Removal of old paint and residue
• Replacement of both bearings (front and rear)
• Installation of a new Ogura SBR-112V-200B brake
• Encoder replaced, newly aligned, and calibrated
• New seals and connectors installed
• Housing repainted and oven-dried
• Final testing on the Yaskawa Sigma-II test stand using the original SGDH-15DE drive

The test included:

• Insulation measurement between phase and housing
• Torque and no-load current verification
• Monitoring of encoder signal quality (sin/cos integrity)
• Brake function test (holding torque, response time)
• Two-hour endurance test under load

After passing all tests, the motor was returned to the customer.
Total repair time: 5 working days.

The customer placed particular emphasis on operational safety, as a Y-axis malfunction could have led to tool crashes.
Thanks to the preventive complete overhaul, long-term reliability of the drive system was restored.

Information about the mentioned Servopack and Servomotor:

• Yaskawa SGMGH-13DCA6H AC Servo Motor
• Encoder Yaskawa UTSIH-B17CK
• Ogura-Bremse SBR-112V-200B (24 VDC)
• Yaskawa Servopack SGDH-15DE

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 motor is used in precision CNC machines, typically:

• Hurco vertical machining centers (Y-axis)
• DMG MORI, Spinner, and Bridgeport machines
• Handling systems and tool changers

Compatible servo drives:
Yaskawa SGDH-10DE to SGDH-15DE
with 17-bit feedback via UTSIH protocol and standard Yaskawa connectors.

Function Description

The SGMGH-13DCA6H-OY is a high-precision AC servo motor of the Sigma II series.
It converts electrical power into controlled torque and rotation.

Key functions:

• Feed axis positioning
• Torque and speed control
• Absolute feedback via UTSIH encoder
• Brake hold when power is off

The built-in brake ensures static holding; it is not intended for emergency stops.

Alarm Codes & Troubleshooting

Main Components