Yaskawa SGMSS-20A2A-YR12 AC Servo Motor – Sigma-V Series

Yaskawa SGMSS-20A2A-YR12: Sigma-V Series 2.0 kW Servo Motor in Closed-Loop Motion Control Architecture

The SGMSS-20A2A-YR12 is a 2.0 kW, 200 V AC servo motor from Yaskawa Electric’s Sigma-V (Σ-V) Series, designed for deterministic torque and velocity control in high-cycle industrial motion systems. Its role within a servo loop is not merely to convert electrical energy into mechanical rotation — it functions as the terminal actuator in a tightly coupled feedback chain that includes a 20-bit absolute encoder, a SGDV-series digital servo amplifier, and the host controller’s position command bus. The motor’s mechanical and electromagnetic design parameters directly govern the achievable bandwidth of the entire closed-loop system.

In axis-positioning applications such as CNC machining centers and multi-joint robotic arms, the SGMSS-20A2A-YR12 operates under continuous current regulation at switching frequencies up to 16 kHz within the paired SGDV amplifier. The motor’s low-inertia rotor construction — combined with a high slot-fill winding — produces a torque constant (Kt) that allows the amplifier’s current loop to achieve gain crossover frequencies above 1 kHz, enabling position loop bandwidths of 300–500 Hz without mechanical resonance excitation. This is the physical basis for the sub-10 ms settling times observed in high-speed pick-and-place and register-mark tracking applications.

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Technical Parameters

Hardware Logical Analysis

Electromagnetic Architecture & EMC Design
The SGMSS-20A2A-YR12 uses a distributed winding topology on a laminated silicon-steel stator core with a slot pitch optimized to minimize cogging torque below 0.5% of rated torque. This is not a cosmetic specification — cogging directly injects periodic disturbance into the velocity loop at a frequency equal to (speed × pole pairs × slots / 60), which at 3,000 rpm manifests as a 900 Hz ripple component. Yaskawa’s slot geometry suppresses this to a level below the noise floor of the encoder feedback, preventing the servo amplifier’s velocity observer from generating compensatory current commands that would otherwise appear as audible motor whine and thermal losses.

The motor’s stator winding is wound with a high fill factor using rectangular cross-section conductors in the outer layers, reducing AC resistance at the 16 kHz PWM carrier frequency. This directly lowers I²R losses under high-frequency current ripple, keeping winding temperature within Class F limits even at 100% duty cycle in ambient temperatures up to 40 °C.

20-bit Absolute Encoder — Feedback Chain Integrity
The integrated 20-bit absolute encoder uses a multi-turn optical disc with battery-backed position retention. The serial encoder protocol transmits position data to the SGDV amplifier over a differential RS-422-compatible link at 4 Mbps. Because the encoder is absolute, the motor shaft position is known to within 1/1,048,576 of a revolution immediately upon power-up — no homing cycle is required. In a 10-axis machining center, this eliminates approximately 45–90 seconds of machine initialization time per power cycle, a measurable contribution to OEE (Overall Equipment Effectiveness).

IP67 Sealing Mechanism
The IP67 rating is achieved through a dual-lip shaft seal at the front bearing housing and a fully gasketed terminal box. The shaft seal uses a PTFE-lined primary lip in contact with the shaft, backed by a secondary dust lip, with a grease-filled cavity between them. This arrangement maintains sealing integrity at shaft speeds up to 5,000 rpm without generating significant frictional heat. The terminal box gasket is compressed to a defined crush depth during assembly, verified by torque-controlled fastening — not a field-adjustable parameter.

Thermal Management & Bearing Life
The TENV (Totally Enclosed Non-Ventilated) construction routes heat from the stator winding through the aluminum housing to the external surface. The housing fin geometry is calculated to maintain a thermal resistance of approximately 0.8 °C/W between winding and ambient at rated load. Bearing preload is set at the factory to achieve L10 bearing life exceeding 30,000 hours at rated speed and radial load, using deep-groove ball bearings with C3 internal clearance and grease fill rated to 150 °C.

System Integration Benefits

• Plug-and-play encoder recognition: The SGDV amplifier reads the motor’s electronic nameplate from the encoder EEPROM at power-up, automatically loading rated current, speed, and inertia parameters — eliminating manual parameter entry errors during commissioning.
• Adaptive vibration suppression: The paired SGDV amplifier implements a dual-notch filter with automatic frequency detection, suppressing mechanical resonances in the range of 100–4,000 Hz without manual spectrum analysis by the commissioning engineer.
• MECHATROLINK-II/III compatibility: The motor-amplifier pair integrates directly into Yaskawa MP-series and third-party MECHATROLINK motion networks, enabling synchronized multi-axis interpolation with a 0.5 ms network cycle time.
• Absolute position retention across power cycles: Battery-backed multi-turn encoder data is retained for a minimum of 3 years with the standard battery, eliminating homing routines and protecting machine coordinates after emergency stops or planned shutdowns.
• Torque ripple below 2% of rated: The combination of sinusoidal current control in the SGDV and the motor’s low-cogging design produces torque ripple below 2% at rated speed, directly reducing surface finish variation in grinding and turning applications.
• Integrated diagnostic transparency: The SGDV amplifier logs motor winding temperature (via thermistor embedded in the stator), encoder battery voltage, and cumulative operating hours — all readable via SigmaWin+ or MECHATROLINK parameter access without interrupting production.
• Regenerative energy handling: During deceleration, the motor operates as a generator. The SGDV’s internal regenerative resistor circuit handles up to 40 W of continuous regenerative power; for high-inertia or frequent-braking applications, the external JUSP-RA04-E resistor extends this capacity to 400 W, preventing DC bus overvoltage faults.
• Safe Torque Off (STO) readiness: When paired with the SGDV-OSA01A safety module, the system achieves SIL 2 / PLd Safe Torque Off per IEC 61800-5-2, enabling integration into safety-rated machine guarding circuits without an external contactor in the motor power line.

Quality Assurance & Global Logistics

Every SGMSS-20A2A-YR12 unit dispatched from our Xiamen, China facility is a genuine Yaskawa-manufactured component sourced through verified industrial supply channels. Each unit undergoes the following pre-shipment verification protocol:

• Visual inspection of shaft, flange face, encoder connector, and terminal box for transit damage or corrosion
• Insulation resistance test: ≥100 MΩ at 500 VDC between winding and frame, per IEC 60034-1
• Encoder communication check: serial link integrity verified with a SGDV test amplifier, confirming absolute position data transmission without CRC errors
• Shaft runout measurement: ≤0.02 mm TIR at the shaft end, per Yaskawa mechanical tolerance specification
• Anti-static and moisture-barrier packaging: motor wrapped in ESD-safe film, placed in a rigid foam-lined carton with silica gel desiccant, sealed with humidity indicator card

Logistics from Xiamen operate via DHL Express, FedEx International Priority, and UPS Worldwide Expedited. Standard transit times are 3–5 business days to Europe and North America, 2–3 business days to Southeast Asia and Japan. All shipments include a commercial invoice with HS Code 8501.52 (AC motors, multi-phase, 750 W–75 kW) for customs clearance. Export documentation, including a certificate of origin and packing list, is provided with every order. For orders requiring air freight consolidation or sea freight for bulk quantities, our logistics team coordinates directly with the buyer’s freight forwarder.

The 12-month warranty covers manufacturing defects in materials and workmanship. DOA (Dead on Arrival) units confirmed within 7 days of receipt are replaced with priority shipment at no additional freight cost. Warranty claims require the unit serial number and a brief fault description; our technical team responds within 1 business day.

Contact Information

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