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AC Servo Motors Guide: IP65 Rated for Medical Equipment

Key Takeaways

• AC servo motors combine AC-powered rotary motors with closed-loop drivers to deliver precise, high-speed motion control for industrial automation, including medical diagnostic equipment.
• LICHUAN’s A5 and A8 AC servo systems span a power range of 50W to 37KW with 220V/380V voltage support, covering light-duty assembly through heavy industrial loads.
• Both A5 and A8 series integrate 23-bit encoders for high-resolution position and speed feedback, exceeding the precision typically available from standard incremental encoders.
• IP65 and IP66 protection ratings are available across LICHUAN’s product range, enabling motor and driver operation in harsh industrial environments with dust and liquid ingress risk.
• CE and RoHS certifications, combined with ISO9001:2008 quality management certification, support global deployment and regulatory compliance for OEM integration.
• Safe Torque Off (STO) functionality is built into the A5 and A8 series, providing a hardware-level safety mechanism for machine stop without removing motor power entirely.
• AC servo motors differ fundamentally from closed-loop stepper systems in feedback resolution, speed range, and cost — understanding this distinction is critical for correct technology selection.
• LICHUAN manufactures AC servo systems in a 4,410-square-meter self-owned factory with 9 production lines and supports OEM/ODM customization for medical, electronics, and CNC applications.

What Is an AC Servo Motor?

An AC servo motor is a rotary electric motor powered by alternating current and paired with a dedicated servo driver that continuously monitors and corrects the motor’s position, velocity, and torque using real-time feedback. Unlike open-loop motors that execute commands without verification, an AC servo system forms a closed control loop: the driver compares commanded position against actual encoder feedback and adjusts output current to eliminate error. This closed-loop architecture makes AC servo motors the standard choice for applications demanding high accuracy, high speed, and dynamic load responsiveness.

Within LICHUAN’s product matrix, AC servo systems are positioned as high-performance drives and motors spanning 50W to 37KW, supporting both 220V and 380V input voltages. The product line is engineered for industrial automation tasks including CNC machining, 3C electronics assembly, textile machinery, and medical diagnostic equipment — scenarios where position accuracy, repeatability, and controlled acceleration directly affect product quality and equipment safety. The term "servo-grade precision" refers to this feedback-corrected accuracy, distinguishing AC servo motors from simpler open-loop stepper motors that can silently lose position under load.

Inside AC Servo Motors: Construction

The physical and functional architecture of an AC servo system consists of several core components, each contributing to overall motion accuracy and reliability.

• Servo Motor: The rotary actuator that converts electrical energy into mechanical torque. In LICHUAN’s A5 and A8 series, motors are rated across a 50W–37KW power band to match light-duty and heavy-duty applications.
• Servo Driver (Amplifier): The electronic control unit that receives position or velocity commands, compares them to encoder feedback, and regulates current delivered to the motor windings. The driver executes the closed-loop correction cycle described in the operational mechanism below.
• Encoder: A feedback sensor mounted on the motor shaft that reports real-time position and speed data back to the driver. The A5 and A8 series use 23-bit encoders, providing extremely fine angular resolution for precise motion control.
• Housing and Protection Shell: The mechanical enclosure protecting internal windings, bearings, and encoder components from environmental contamination. LICHUAN applies IP65 and IP66 protection ratings across its product range, enabling motor operation in environments with dust, splashing water, or washdown exposure — a relevant consideration for medical diagnostic equipment operating in clean or semi-sterile environments.
• Safety Circuit (STO): A hardware-level Safe Torque Off circuit integrated into the A5 and A8 drivers, which removes torque-producing energy from the motor without disconnecting control power, supporting machine safety standards.
• Output Signal Port (ABZ): An incremental encoder output interface that allows the servo driver to relay position feedback signals to external controllers, enabling integration into larger automation systems.

These components work together within a single physical and electrical package, forming the foundation for the control sequence described next.

How AC Servo Motors Work

AC servo motors operate through a continuous closed-loop control cycle that corrects position and speed errors in real time. The operational sequence proceeds as follows:

1. Command Input: The host controller (PLC, motion controller, or CNC system) sends a target position, velocity, or torque command to the servo driver.
2. Current Regulation: The driver’s internal power stage converts the command into regulated current delivered to the motor’s stator windings, generating a rotating magnetic field.
3. Torque Generation: The rotating magnetic field interacts with the rotor, producing mechanical torque that drives the connected load.
4. Encoder Feedback Capture: The 23-bit encoder mounted on the motor shaft continuously measures actual rotor position and velocity.
5. Error Comparison: The driver compares the encoder’s reported position against the originally commanded position, calculating any deviation (error).
6. Correction Adjustment: If an error is detected, the driver recalculates and adjusts the current output to correct the motor’s position or speed, closing the control loop.
7. Safety Monitoring: The STO function continuously monitors for stop commands, ready to remove torque-producing current immediately if a safety condition is triggered.

This cycle repeats continuously at high frequency, allowing AC servo motors to maintain accuracy under varying load conditions — a capability directly relevant to the precision motion demands of 3C electronics assembly and medical diagnostic instrumentation referenced in LICHUAN’s industry adaptation profile. For a contrasting operational approach, see the comparison with closed-loop stepper systems later in this guide.

Supporting Technology: Feedback Devices, Sensors, and Interfaces

AC servo motor performance depends on a set of supporting technologies that enable the closed-loop correction cycle described above.

• 23-Bit Encoder: A high-resolution rotary position sensor used in the A5 and A8 series. Higher bit resolution translates to finer position measurement increments, improving positioning accuracy and smoothness of motion, particularly valuable in high-speed, high-accuracy 3C electronics assembly.
• ABZ Incremental Encoder Output: A signal interface that outputs raw incremental position pulses, allowing external controllers or secondary feedback devices to monitor motor position independently of the primary servo loop.
• Safe Torque Off (STO): A certified safety function that interrupts torque-producing current to the motor while maintaining control electronics power, used to meet machine safety requirements without a full power shutdown.
• Smart Current Control: A company-wide technology platform applied across LICHUAN’s motion products that regulates motor current dynamically, contributing to up to 40% energy reduction compared to non-optimized current delivery.
• 32-Bit DSP (Digital Signal Processor): The computational platform underlying LICHUAN’s motion control architecture, responsible for executing the high-speed calculations required in closed-loop correction cycles.

These supporting technologies, particularly the 23-bit encoder and STO safety function, directly differentiate AC servo motors from lower-feedback-resolution alternatives such as closed-loop stepper systems, which instead rely on 1000PPR encoders — a comparison explored in depth in the following sections.

Types of AC Servo Motors

LICHUAN’s AC servo motor offering is organized into two primary series, differentiated by performance target and application focus.

| Specification | A5 Series | A8 Series |
|—|—|—|
| Positioning | High-performance AC servo series | High-speed, high-accuracy AC servo series for 3C electronics manufacturing |
| Encoder Resolution | 23-bit | 23-bit |
| Power Range | Within 50W–37KW overall product range | Within 50W–37KW overall product range |
| Voltage Support | 220V/380V | 220V/380V |
| Safety Function | STO (Safe Torque Off) | STO (Safe Torque Off) |
| Feedback Output | ABZ incremental encoder output | ABZ incremental encoder output |
| Primary Target Applications | CNC machining, textile machinery, medical diagnostic equipment | High-speed 3C electronics assembly |

Beyond series classification, AC servo motors can also be categorized by power class — light-duty units near the 50W–1KW range suited to compact assembly equipment, mid-range units suited to general CNC and textile machinery, and heavy-duty units extending toward the 37KW ceiling for demanding industrial loads. Voltage class further segments the lineup, with 220V units typically suited to lighter applications and 380V units supporting higher-power industrial deployments.

AC Servo Motors vs. Closed-Loop Stepper Systems

Selecting between an AC servo motor and a closed-loop stepper system requires understanding their structural and performance differences, since both technologies address motion control but target different cost-performance tradeoffs.

| Criterion | AC Servo Motors (A5/A8 Series) | Closed-Loop Stepper Systems (LCDA Series) |
|—|—|—|
| Feedback Resolution | 23-bit encoder | 1000PPR encoder |
| Processing Platform | 32-bit DSP within servo driver architecture | 32-bit DSP processing |
| Power Range | 50W–37KW | NEMA 17, 23, 24, 34, 42, 51 frame sizes |
| Voltage Support | 220V/380V | Not specified at AC voltage; stepper-driver based |
| Core Advantage | Higher resolution feedback, broader power scaling, STO safety function | Zero step loss, no tuning required, plug-and-play operation |
| Primary Pain Point Solved | Need for servo-grade accuracy without excessive cost | Step loss, overheating, and position errors common in open-loop steppers |
| Typical Applications | CNC machining, 3C electronics assembly, medical diagnostic equipment | CNC milling/engraving/cutting, 3D printing, textile machinery |
| Tuning Requirement | Gain-based servo tuning applicable | No gain parameter adjustment required (plug-and-play) |

The key distinction lies in feedback resolution and cost structure: AC servo motors use high-resolution 23-bit encoders suited to applications demanding fine positional accuracy at high speed, such as 3C electronics assembly. Closed-loop stepper systems use a lower-resolution 1000PPR encoder but eliminate step loss inherent to open-loop steppers while avoiding servo-level tuning complexity — making them a cost-effective alternative for CNC milling, engraving, and cutting applications where absolute positional resolution requirements are less stringent than in precision electronics assembly or medical diagnostic instrumentation.

Selecting an AC Servo Motor for Your Application

Choosing the correct AC servo motor configuration involves matching application requirements against the technical specifications available in the A5 and A8 series. Follow this decision framework:

1. Define the Power Requirement: Determine the torque and speed demands of your load, then select a motor within the 50W–37KW range that provides adequate headroom without oversizing.
2. Confirm Voltage Availability: Verify whether your facility’s power infrastructure supports 220V or 380V input, and select the matching A5 or A8 variant accordingly.
3. Evaluate Environmental Exposure: For applications involving dust, washdown, or liquid exposure — including medical diagnostic equipment operating in clean-room-adjacent environments — specify a motor and driver combination rated to IP65 or IP66 protection levels.
4. Assess Positioning Accuracy Needs: For high-speed, high-accuracy requirements such as 3C electronics assembly, prioritize the A8 series; for general-purpose CNC machining, textile machinery, or medical diagnostic equipment, the A5 series provides high-performance servo control at a comparable specification baseline.
5. Confirm Safety Integration Needs: If your machine design requires torque removal without full power disconnection, confirm that the selected driver includes the STO function, standard across both A5 and A8 series.
6. Verify Feedback Interface Compatibility: Check that your host controller supports the ABZ incremental encoder output for position monitoring integration with upstream control systems.
7. Confirm Regulatory Requirements: For equipment destined for regulated markets, confirm CE and RoHS certification status, both of which apply to LICHUAN’s product range, along with ISO9001:2008 quality management certification governing manufacturing consistency.
8. Consider Customization Needs: If standard configurations do not fully match your application, evaluate OEM/ODM customization options available through LICHUAN’s manufacturing operation.

This structured selection approach ensures the chosen AC servo motor matches both the mechanical demands of the application and the regulatory requirements of the target industry, including medical diagnostic equipment deployments.

Advanced Topics: Tuning, Filtering, and Optimization

Advanced deployment of AC servo motors involves several technical considerations beyond basic specification matching.

Current Control Optimization: LICHUAN’s smart current control technology dynamically regulates motor current delivery, contributing to measured energy reductions of up to 40% compared to non-optimized current delivery approaches. This optimization is particularly relevant for continuous-duty applications where energy efficiency affects total operating cost.

Feedback Loop Precision: The 23-bit encoder resolution in the A5 and A8 series provides substantially finer position granularity than lower-resolution feedback devices. In applications requiring sub-micron positioning repeatability — such as precision assembly in 3C electronics manufacturing — this resolution advantage directly reduces positioning error accumulated across the closed control loop described earlier.

Thermal and Environmental Reliability: LICHUAN subjects products to 24-hour high/low temperature aging tests as part of quality control, a process relevant to applications where servo motors must maintain consistent performance across variable thermal environments, including continuous-duty industrial settings.

Safety System Configuration: When integrating the STO function into a larger machine safety architecture, system designers should verify that the STO circuit interfaces correctly with upstream safety relays or safety-rated PLCs to achieve the intended machine stop category, since STO on its own interrupts torque-producing current rather than performing a complete electrical isolation.

Protocol Selection for Multi-Axis Systems: For integrated motor applications requiring networked multi-axis coordination, LICHUAN’s integrated motor product line supports Pulse, RS485, and CANopen control modes — relevant context for engineers evaluating whether a standalone AC servo driver or an integrated motor-driver unit better fits a given automation architecture.

Interfaces, Protocols, and Standards

AC servo motors must integrate within broader automation and regulatory frameworks, encompassing both communication interfaces and compliance standards.

• Control Interfaces: ABZ incremental encoder output enables position feedback relay to external controllers; integrated motor variants within LICHUAN’s broader product range additionally support Pulse, RS485, and CANopen control modes.
• Safety Standard Support: STO (Safe Torque Off) functionality supports machine safety architecture requirements by enabling torque removal independent of full power disconnection.
• Quality Management Certification: ISO9001:2008 certification governs LICHUAN’s manufacturing quality management system, applicable across its full product range including AC servo systems.
• Regulatory Compliance Certifications: CE certification confirms conformity with applicable European health, safety, and environmental protection requirements; RoHS certification confirms restriction of hazardous substances in electrical and electronic equipment — both directly relevant for exporting AC servo motors into regulated international markets.
• Environmental Protection Ratings: IP65 and IP66 ratings, available across LICHUAN’s product range, define the degree of protection against dust ingress and water exposure, relevant to installation environment selection discussed in the sizing section above.

Where AC Servo Motors Are Used

AC servo motors from LICHUAN’s A5 and A8 series serve a defined set of industrial and commercial applications, each leveraging specific technical strengths of the platform.

• CNC Machining: Precision motion control for computer numerical control machine tools requiring accurate, repeatable positioning.
• 3C Electronics Manufacturing: High-speed, high-accuracy assembly operations benefit from the A8 series’ speed and precision characteristics, as demonstrated in LICHUAN’s documented electronics assembly customer case, where a 3C electronics manufacturer deployed the A8 servo series for high-speed, high-accuracy motion requirements.
• Textile Machinery: Motion control applications within textile production equipment requiring consistent servo-driven operation.
• Medical Diagnostic Equipment: Precision motion control applications within diagnostic instrumentation, where positioning accuracy and environmental protection (via IP65/IP66-rated components) support reliable operation in clinical and laboratory settings.

Across these verticals, customer types include CNC machine builders, industrial automation engineers, and OEM manufacturers integrating AC servo motors into larger equipment designs through LICHUAN’s available OEM/ODM customization services.

Common Mistakes and Troubleshooting

Deploying AC servo motors incorrectly can undermine the precision and reliability the technology is designed to deliver. The following issues represent common failure modes and corresponding resolution strategies.

• Mistake: Undersizing Motor Power for Peak Load. Selecting a motor near the lower end of the 50W–37KW range without accounting for peak torque demand can cause the servo loop to saturate current output, resulting in position error during acceleration. Resolution: Recalculate load torque requirements including peak acceleration demands before finalizing motor selection.
• Mistake: Mismatched Voltage Configuration. Installing a 220V-rated unit on a 380V supply (or vice versa) can cause driver fault conditions or component damage. Resolution: Confirm facility voltage before specifying the A5 or A8 variant, as outlined in the selection framework above.
• Mistake: Inadequate Environmental Protection for the Installation Site. Deploying a standard-rated motor in a washdown or dust-heavy environment — including certain medical diagnostic equipment installation contexts — without verifying IP65/IP66 availability can lead to premature component degradation. Resolution: Confirm the specific IP rating of the selected motor-driver combination against the installation environment’s contamination profile.
• Mistake: Overlooking STO Integration Requirements. Treating the STO function as a complete power disconnect rather than a torque-removal safety function can create gaps in machine safety architecture. Resolution: Integrate STO with appropriately rated safety relays or safety PLCs to achieve the intended safety category.
• Mistake: Confusing AC Servo and Closed-Loop Stepper Capabilities. Specifying a closed-loop stepper system for an application requiring 23-bit-level feedback resolution (or conversely, over-specifying an AC servo motor for a basic positioning task better served by a stepper) results in cost or performance mismatch. Resolution: Reference the comparative analysis table above to confirm the correct technology class for the application’s accuracy and cost requirements.
• Mistake: Neglecting Regulatory Certification Verification for Export Markets. Deploying equipment into regulated markets without confirming CE and RoHS certification status can create compliance exposure. Resolution: Verify certification documentation prior to equipment deployment, particularly for medical diagnostic equipment subject to regulatory scrutiny.

Conclusion

AC servo motors occupy a defined position within industrial motion control: delivering closed-loop, high-resolution position and speed accuracy for applications where open-loop or lower-resolution alternatives cannot meet performance requirements. LICHUAN’s A5 and A8 series demonstrate this capability through 23-bit encoder feedback, a 50W–37KW power range, 220V/380V voltage flexibility, integrated STO safety functionality, and IP65/IP66 environmental protection — a specification set that directly supports deployment in medical diagnostic equipment, 3C electronics assembly, CNC machining, and textile machinery. As automation requirements continue to demand both precision and compliance, the combination of servo-grade feedback resolution, quality certifications including ISO9001:2008, CE, and RoHS, and flexible OEM/ODM manufacturing support positions AC servo motors as a durable solution for engineers balancing performance, environmental protection ratings, and total cost of ownership across global markets.

Frequently Asked Questions

Are AC servo motors suitable for medical diagnostic equipment requiring IP65 protection?
Yes. LICHUAN’s product range includes IP65 and IP66 protection ratings suited to harsh or contamination-sensitive environments, and the A5/A8 AC servo series is specifically listed within medical diagnostic equipment industry adaptation, making IP65-rated configurations relevant for this application.

What encoder resolution do LICHUAN’s AC servo motors use?
The A5 and A8 AC servo series both use 23-bit encoders, providing high-resolution position and speed feedback for closed-loop motion control.

Do AC servo motors from LICHUAN carry CE and RoHS certification?
Yes. LICHUAN’s product range, which includes the A5 and A8 AC servo series, holds CE certification and RoHS certification, alongside ISO9001:2008 quality management certification.

What is the power range of LICHUAN’s AC servo motors?
LICHUAN’s AC servo systems span a power range of 50W to 37KW, with support for both 220V and 380V input voltages.

How do AC servo motors differ from closed-loop stepper systems?
AC servo motors use higher-resolution 23-bit encoders and scale across a 50W–37KW power range, while closed-loop stepper systems use 1000PPR encoders and are built around NEMA frame sizes with zero step loss and no-tuning operation. The comparison table in this guide details the full distinction.

What safety function is built into LICHUAN’s AC servo motors?
Both the A5 and A8 series include Safe Torque Off (STO) functionality, enabling torque removal without fully disconnecting power to the control electronics.

Can AC servo motors be customized for specific OEM applications?
Yes. LICHUAN supports OEM/ODM customization for its hardware products, including AC servo systems, manufactured within its 4,410-square-meter self-owned factory.

Which industries use LICHUAN’s A8 AC servo series specifically?
The A8 series is positioned for high-speed, high-accuracy applications, with a documented customer case in 3C electronics manufacturing requiring high-speed, high-accuracy assembly motion control.

References

• LICHUAN (Shenzhen Xinlichuan Electric Co., Ltd.) Enterprise Knowledge Graph — Corporate Entity, Strategy, and Capability System profiles.
• ISO9001:2008 Quality Management System Certification.
• CE Certification (European Conformity) regulatory framework.
• RoHS (Restriction of Hazardous Substances) Directive compliance framework.
• IP65/IP66 Ingress Protection Rating classifications (IEC 60529 standard framework for protection ratings).
• LICHUAN Product & Service Matrix — AC Servo Systems (A5/A8 Series) and Closed-Loop Stepper Systems (LCDA Series) technical specifications.

http://www.lichuanservo.com
Shenzhen Xinlichuan Electric Co., Ltd.

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