The YASKAWA SGMSS-20A2A-YR12 is an AC servo motor designed for closed-loop motion systems where the goal is not simply rotation, but controlled rotation: precise torque, repeatable speed behavior, and reliable positioning when paired with a compatible servo drive and motion controller. In industrial automation and robotic subsystems, a servo motor like the SGMSS-20A2A-YR12 is selected because it behaves predictably under changing loads, frequent acceleration/deceleration cycles, and continuous production schedules.
Unlike general-purpose induction motors, servo motors are built around the idea that the motor is only one part of a feedback-driven control loop. The controller issues a command, the servo drive shapes current and voltage to generate torque, and the motor returns feedback so the drive can correct errors in real time. The practical benefit is simple: when everything is installed and tuned correctly, the axis hits target speeds quickly, settles without “hunting,” and repeats the same move thousands of times with consistent results.
The SGMSS family is commonly associated with compact, automation-focused servo designs and appears in many equipment platforms and retrofit projects. In the field, this model format is often seen in applications where a 2 kW-class servo motor is used for indexing, positioning, or axis actuation—especially where the machine builder cares about cycle time without sacrificing smoothness. If your system is a robot axis, a packaging station, a feeder, an indexing table, or a precision handling mechanism, the motor’s real job is to convert electrical control into mechanical stability while keeping response sharp and repeatable.
Why the SGMSS-20A2A-YR12 matters in real machines
1) Stable torque delivery helps protect mechanics
Fast motion is easy to ask for; controlled motion is harder. Poorly controlled torque can create shock loads that loosen couplings, fatigue bearings, and amplify vibration in frames. A properly matched servo motor helps the drive produce torque smoothly, which reduces hidden wear. Over months of production, that can be the difference between a line that stays calibrated and one that needs constant mechanical attention.
2) Repeatability improves yield and reduces tuning drama
Production equipment rarely operates under perfect conditions. Friction changes, belts warm up, grease thickens in winter, and payloads vary. A servo motor with predictable response makes tuning less fragile. Instead of constantly chasing oscillation, overshoot, or settling issues, you can aim for a stable tuning profile that stays stable across day-to-day variation.
3) Designed for cyclic duty
Many servo axes live in a loop: accelerate, move, decelerate, dwell, repeat. This stresses the motor thermally and mechanically. Servo motors in this category are typically used where frequent cycling is normal, and the system is sized based on RMS (root-mean-square) load over time rather than just peak torque.
Key Product Details (Quick Reference Table)
| Item | Description |
|---|---|
| Brand | YASKAWA |
| Model | SGMSS-20A2A-YR12 |
| Product Type | AC Servo Motor (SGMSS Series) |
| Typical Output Class | 2.0 kW class (commonly referenced for SGMSS-20A2A variants) |
| Typical Rated Speed (Reference) | 3000 rpm class is commonly listed for SGMSS-20A2A variants |
| Typical System Voltage (Reference) | 200 V class commonly listed for SGMSS-20A2A variants |
| Feedback | Designed for servo feedback operation within compatible Yaskawa drive systems |
| Common Use Scenarios | Automation axes, indexing tables, robotic sub-axes, handling mechanisms, retrofit replacements |
| Approx. Motor Weight (Net Reference) | Approx. 7.26 kg |
| Packaged Weight (Related 2.0 kW robot-axis motor example) | Approx. 10 kg |
Weight note (so you don’t get burned in shipping calculations)
Online sources often mix net motor weight with packaged shipping weight, which can differ significantly due to foam, boxes, brackets, and protective packing. For procurement and logistics, treat the ~7.26 kg figure as a practical net reference for this 2 kW SGMSS-20A2A class, and treat shipping weight as system- and supplier-dependent.
Integration-focused explanation (what engineers actually care about)
Mechanical fit and alignment
Most servo problems blamed on “electronics” are mechanical problems wearing an electronics costume. Misalignment, coupling strain, bent shafts, or pulley runout will show up as vibration, noise, inconsistent positioning, and shortened bearing life. With a motor in this class, treat alignment as a commissioning requirement, not a suggestion. If you are coupling to a gearbox or ball screw, check concentricity and angular alignment carefully; if you are using belts, verify pulley alignment and belt tension consistency.
Feedback signal quality and wiring discipline
Servo feedback is the drive’s sensory system. When feedback wiring is noisy or poorly grounded, you can see intermittent alarms, jitter at low speed, or unstable holding behavior. The fix is rarely “change the motor”; it is usually cable routing, shield termination, connector integrity, and a clean grounding scheme in the cabinet. Keep power cables and encoder/feedback cables separated, avoid parallel runs where possible, and follow industrial EMC practice.
Thermal sizing and RMS load
A motor can survive a short burst of high torque but still fail early if the continuous thermal load is too high. RMS torque (and the duty cycle) matters more than peak torque for long-term reliability. If your application does aggressive stop-start cycles, frequent reversals, or high acceleration profiles, ensure the system is sized with thermal headroom. This reduces temperature rise, improves bearing life, and lowers the probability of nuisance trips.
Typical application scenarios
The SGMSS-20A2A-YR12 is a fit for motion axes where both responsiveness and stability matter:
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Robot or robotic sub-axis systems where repeatable movement and controlled torque reduce stress on transmissions and joints
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Indexing tables and rotary stations where position repeatability directly affects assembly accuracy
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Packaging and converting machines where quick acceleration must still settle cleanly to protect registration and cut quality
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Precision material handling such as feeders, pushers, or pick-and-place fixtures that require consistent cycle timing
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Retrofit projects replacing aged servo motors to restore closed-loop performance and reduce downtime
Summary
The YASKAWA SGMSS-20A2A-YR12 is an industrial AC servo motor intended for closed-loop motion systems that demand controlled torque, stable dynamic response, and repeatable performance over long production cycles. For machine builders and maintenance teams, the value is not theoretical horsepower; it is the practical outcome: smoother motion, fewer tuning headaches, and a more stable process window. For logistics and planning, an approximate net weight reference around 7.26 kg is commonly cited for this 2 kW SGMSS-20A2A class, while shipping weight can be substantially higher depending on packaging.
