15.09.2025 by Viktor Siebert
Yaskawa SGMG-09A2AB Motor HAAS Type 93-0346 with Encoder UTOPH-81AWF from HAAS VF4, Repairstory
A HAAS VF4 CNC Machine was reported with Y-axis issues: sporadic positioning errors and unusual noise. Upon removal, the SGMG-09A2AB motor showed contamination, oil mist around seals, and play in the front bearing. The UTOPH-81AWF encoder provided faulty feedback signals.
If the motor had continued running, it could have caused sudden machine stoppage, tool breakage, and production downtime.
The preventive repair process:
- Bearings, seals, and connectors replaced
- Complete cleaning in emulsion bath, followed by oven drying
- Encoder replaced, programmed, and calibrated
- Insulation tested, shaft current measured
- Final test run: load simulation, signal quality, thermal behavior verified
Causes of Motor & Encoder Failures
- Temperature fluctuations → condensation
- Oil and coolant mist
- Vibrations from machining forces
- Aging of cables and connectors
- Dust and chips in the environment
- Gradual process: sporadic errors → frequent errors → final failure
Preventive Tips for Customers
- Keep the machine environment clean and dry
- Inspect cables and connectors regularly
- Reduce vibrations where possible
- Avoid rapid temperature changes
- Perform preventive overhauls every 5–7 years
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.
Technical Specifications
| Parameter | Value |
|---|
| Motor Type | Yaskawa SGMG-09A2AB, HAAS Type 93-0346 |
| Manufacturer | Yaskawa Electric, Japan |
| Rated Power | 850 W |
| Rated Torque | 5.39 Nm |
| Rated Speed | 1500 rpm |
| Peak Torque | approx. 15–16 Nm (according to curve) |
| Rated Current | 7.1 A |
| Supply Voltage | 200 V AC (3~) |
| Frequency | 50/60 Hz |
| Insulation Class | F |
| Protection Class | IP65 (except shaft) |
| Encoder | UTOPH-81AWF, 8192 PPR incremental |
| Frame Size | approx. 130 mm flange, ~9 kg |
| Cooling | Self-cooled (Totally Enclosed, Fanless) |
Application & Compatible Devices
This motor is used in HAAS VF4 CNC machining centers. Typical applications include axis drives (X/Y/), tool movements, and precision positioning tasks.
Compatible amplifiers:
- Yaskawa SGDB series (Sigma Servo Amplifier)
- HAAS-specific servo amplifier modules
Functional Description
The motor is a permanent magnet AC servo motor, designed for high precision and dynamic performance. The UTOPH-81AWF encoder (8192 PPR) provides accurate position feedback to the control system.
Advantages:
- Smooth operation and high accuracy
- Robust design for industrial CNC environments
- Long service life due to sealed bearings and protected housing
Alarms & Troubleshooting
| Code | Error Description | Cause | Solution |
|---|
| A.01 | Overcurrent | Short circuit or overload | Check load, test drive |
| A.02 | Overvoltage | Supply voltage too high | Check input |
| A.03 | Undervoltage | Supply voltage too low | Verify input |
| A.06 | Motor Overheat | Blocked airflow, ambient too hot | Improve cooling, clean motor |
| A.07 | Drive Overheat | Excessive continuous load | Improve ventilation |
| A.11 | Encoder Error | Damaged cable/connector, weak LED | Inspect/replace encoder |
| A.12 | Encoder Battery Low | Aged or defective battery | Replace battery |
| A.15 | Torque Error | Motor blocked | Inspect mechanics |
| A.21 | Communication Error | Signal loss to controller | Check wiring/signals |
| A.23 | Position Error | Overload, wrong parameters | Adjust parameters |
Components
| Component | Description |
|---|
| Rotor | Permanent magnet rotor |
| Stator | Winding assembly |
| Encoder | UTOPH-81AWF, 8192 PPR |
| Bearings | Precision ball bearings |
| Housing | Aluminium, black anodized |
| Seals | IP65, oil and dust resistant |
| Connectors | Power & encoder connectors |
| Shaft | Keyway execution |