YASKAWA SGMG-30ASA AC Servo Motor – Sigma-II

YASKAWA SGMG-30ASA: Medium-Inertia 3 kW Servo Motor for High-Torque Closed-Loop Axes

The SGMG-30ASA is a 3.0 kW, 1,500 RPM AC servo motor from YASKAWA Electric Corporation’s Sigma-II (Σ-II) platform. Engineered for medium-to-high inertia load profiles, this motor occupies a well-defined position in the Sigma-II ecosystem: it delivers 19.1 N·m continuous torque with a 3× instantaneous overload ceiling of 57.3 N·m, making it the preferred actuator for machine tool feed axes, servo press tonnage control, and multi-axis robotic joints where sustained torque density and thermal stability are non-negotiable. The SGMG frame series uses a larger stator diameter than the SGMS (small inertia) family, deliberately increasing rotor inertia to smooth velocity disturbances caused by mechanically coupled loads — a design trade-off that reduces the burden on the velocity loop gain tuning and lowers the risk of mechanical resonance excitation in gearbox-coupled applications.

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Technical Parameters

Hardware Logical Analysis

The SGMG-30ASA’s stator lamination stack is skewed by approximately one slot pitch relative to the rotor magnets. This geometry distributes the cogging force across a wider angular interval, attenuating torque ripple at low speeds to levels below 1% of rated torque — a figure that directly governs surface-finish quality in grinding and honing applications where velocity uniformity at 5–50 RPM is critical. The winding configuration is delta-connected for the 200 V class, which lowers the per-phase inductance compared to a star-wound equivalent and allows the SGDH drive’s current regulator to achieve a higher bandwidth — typically 2–3 kHz current loop bandwidth — without saturation artefacts.

Thermal management in the SGMG frame relies on a finned aluminium housing with an axial heat-flow path from the stator core to the mounting flange. Under continuous rated load at 1,500 RPM, the winding temperature rise above ambient is held within Class F limits (≤115 K above 40 °C ambient), providing a 40 K thermal margin before the Class F insulation threshold is reached. This margin is significant in enclosed cabinet installations where ambient temperatures can reach 50–55 °C during summer operation.

The 2,048 P/R incremental encoder outputs A, B, and Z differential signals (RS-422 compatible) at a line driver output impedance of 110 Ω. At 1,500 RPM, the encoder generates a fundamental frequency of 51.2 kHz per channel — well within the SGDH drive’s input receiver bandwidth of 500 kHz, leaving headroom for future speed range extension. The Z-pulse width is guaranteed at ≥1 electrical degree, ensuring reliable homing even at rapid traverse speeds. EMC shielding on the encoder cable connector shell is bonded to the motor frame ground, forming a continuous Faraday path that suppresses common-mode noise injection into the feedback signal — a detail that becomes critical in installations sharing cable trays with high-current PWM motor power cables.

The IP55 ingress protection is achieved through a labyrinth seal at the shaft exit combined with a gasket-sealed terminal box. The labyrinth geometry creates a tortuous path that prevents coolant mist — typical in machining centre environments — from reaching the bearing cavity without relying on contact seals that would add drag torque and wear. Bearing preload is set at the factory to C3 clearance class, balancing radial stiffness against thermal expansion during warm-up cycles.

System Integration Benefits

• Direct Sigma-II Drive Pairing: The SGMG-30ASA is factory-matched to the SGDH-30AE and SGDM-30ADA drives. Motor code parameters (inertia ratio, encoder resolution, rated current) are pre-loaded in the drive’s EEPROM, eliminating manual parameter entry and reducing commissioning time to under 30 minutes for a single axis.
• Auto-Tuning via SigmaWin+: YASKAWA’s SigmaWin+ software executes an online inertia identification routine that measures the load-to-motor inertia ratio in real time. The result is used to automatically set the speed loop gain (Kv) and integral time constant (Ti), achieving stable settling within 2–3 tuning iterations for most mechanical configurations.
• Vibration Suppression Filter: The SGDH drive paired with this motor supports a two-stage notch filter (adjustable centre frequency 50–5,000 Hz, depth up to −40 dB) that targets mechanical resonance frequencies in the load structure. This allows the velocity loop bandwidth to be raised beyond the first resonance frequency without exciting structural modes — a measurable improvement in throughput for high-cycle pick-and-place applications.
• MECHATROLINK-II Network Compatibility: With the optional JUSP-NS115 option card installed in the SGDH drive, the SGMG-30ASA axis becomes a MECHATROLINK-II node. The 4 ms synchronous cycle time of the network enables deterministic multi-axis electronic gearing and cam profiling without dedicated motion controller hardware.
• Diagnostic Transparency: The SGDH drive continuously monitors motor winding temperature (via thermistor embedded in the stator), encoder signal integrity (A/B differential level monitoring), and instantaneous current deviation from the current reference. All fault events are logged with a timestamp in the drive’s non-volatile alarm history (last 10 events), accessible via the front panel keypad or SigmaWin+ without interrupting production.
• Regenerative Energy Handling: During deceleration, the SGMG-30ASA operates as a generator, returning kinetic energy to the DC bus of the SGDH drive. The drive’s built-in regenerative resistor circuit dissipates this energy when the bus voltage exceeds the overvoltage threshold (approximately 400 VDC for the 200 V class). For high-inertia loads with frequent deceleration cycles, an external regenerative resistor unit (JUSP-RA series) can be connected to increase dissipation capacity without drive replacement.
• Sigma-I Mechanical Interchangeability: The SGMG-30ASA shares the same IEC flange dimensions and shaft geometry as the legacy Sigma-I SGMG-30A, enabling a drop-in mechanical replacement. Only the encoder cable requires adaptation (different connector pinout); the power cable wiring is identical. This reduces retrofit downtime to under two hours per axis in most installations.
• Scalable Multi-Axis Architecture: Multiple SGMG-30ASA axes can be powered from a shared DC bus configuration using YASKAWA’s converter-inverter (CIMR-series) topology, reducing total panel space and improving energy efficiency through bus sharing during mixed acceleration/deceleration cycles across axes.

Quality Assurance & Global Logistics

Every SGMG-30ASA unit supplied by siemensplc.com is sourced from verified YASKAWA distribution channels or authenticated surplus inventory with intact original packaging, date codes, and factory labels. Prior to dispatch from our Xiamen, China facility, each unit undergoes a structured pre-shipment inspection protocol: no-load run test at rated speed, insulation resistance measurement (≥100 MΩ at 500 VDC megger test), encoder A/B/Z signal verification on an oscilloscope, and visual inspection of shaft, flange, and connector integrity. Units that do not pass all checkpoints are quarantined and not shipped.

Export documentation — commercial invoice, packing list, certificate of origin, and HS code declaration (8501.52) — is prepared in-house and complies with Chinese customs export regulations. Air freight via DHL Express or FedEx International Priority delivers to most destinations within 3–7 business days from Xiamen Gaoqi International Airport. Sea freight (LCL or FCL) is available for bulk orders with transit times of 18–35 days depending on destination port. All shipments are insured at declared value. A 12-month warranty covers manufacturing defects; replacement units or full refunds are processed within 5 business days of confirmed fault diagnosis.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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