Yaskawa SGMGH-09DCA6S-OY Sigma II AC Servo Motor

The Yaskawa SGMGH-09DCA6S-OY is a high-inertia AC servo motor from the renowned Sigma II series, engineered for applications requiring high torque output at relatively low speeds. This motor delivers 850 watts of rated power with a rated speed of 1500 revolutions per minute, making it particularly suitable for direct drive of heavy loads such as machine tool feed axes, large industrial robots, injection molding machines, and material handling equipment. The motor operates on a 400 Volt AC three-phase power supply, compatible with industrial power systems in many regions. The high-inertia rotor design provides increased angular momentum, which helps to smooth motion when accelerating and decelerating high-inertia loads, reducing settling time and improving positioning accuracy.

Mechanical and Environmental Design

The SGMGH-09DCA6S-OY features a robust cast aluminum housing with cooling fins for efficient heat dissipation. The frame size is part of the Sigma II SGMGH series, which is larger than the low-inertia SGMPH series. The motor includes a straight shaft with a key and a threaded hole for securing the load. A heavy-duty oil seal is fitted on the shaft to prevent the ingress of cutting fluids, lubricants, or debris, extending the motor’s life in harsh machine tool environments. The motor’s protection rating is IP67, meaning it is fully dust-tight and can withstand temporary immersion in water. This makes it suitable for outdoor or washdown applications. The operating temperature range is 0 to 40 degrees Celsius for ambient air, with a maximum winding temperature rise of 60 degrees Celsius under rated conditions. The motor is certified with CE and UL markings.

Absolute Encoder System

A key feature of the SGMGH-09DCA6S-OY is its 17-bit absolute encoder with a resolution of 131,072 pulses per revolution. Unlike incremental encoders, the absolute encoder retains the motor’s position even after power loss, using a multi-turn counter powered by a battery backup. This eliminates the need for a homing sequence on machine startup, reducing cycle time and simplifying operation. The encoder provides absolute position data over a serial communication link to the servo driver, ensuring noise-immune data transfer. The battery is typically installed in the servo driver or a separate battery unit and must be replaced periodically according to the manufacturer’s schedule. The absolute encoder can also be used in incremental mode if the battery is not desired, but then homing will be required after each power cycle.

Performance Specifications

At the rated speed of 1500 RPM, the motor produces a continuous torque of approximately 5.39 Nm (value may vary by exact variant). The stall torque is similar. The motor can output up to 300 percent of rated torque for short periods, enabling high acceleration rates and the ability to break through static friction. The torque constant (Kt) is defined in the motor’s datasheet, allowing the servo drive to calculate torque from current. The motor’s winding resistance and inductance values are matched to Yaskawa Sigma II drives such as the SGDH series. The maximum rotational speed is typically 3000 RPM, although torque is reduced in the constant power region above rated speed. The motor uses Class F insulation and includes a PTC thermistor for over-temperature protection, connected to the drive to trigger an alarm if the temperature exceeds safe limits.

Integration and Applications

The SGMGH-09DCA6S-OY is designed to be paired with Yaskawa SGDH series servo drivers for complete system operation. The drive provides the necessary power conversion, current control, and communication with the encoder. Application areas include CNC milling machines (feed axes), large pick-and-place robots, palletizers, automated guided vehicles carrying heavy payloads, and printing press drive rollers. The motor’s high inertia makes it particularly adept at driving lead screws and ball screw mechanisms where the load inertia is high. When installing, care should be taken to route power and encoder cables separately to avoid noise coupling. The motor should be mounted on a flat, rigid surface, with proper grounding as specified in the installation manual.