Servo Motor and Drive Selection Key Points

I. Core Motor Selection

Load Analysis

  1. Inertia Matching: Load inertia JL should be ≤3× motor inertia JM. For high-precision systems (e.g., robotics), JL/JM<5:1 to avoid oscillations.
  2. Torque Requirements:Continuous Torque: ≤80% of rated torque (prevents overheating).Peak Torque: Covers acceleration/deceleration phases (e.g., 3× rated torque).
  3. Speed Range: Rated speed must exceed actual maximum speed with 20%–30% margin (e.g., 3000 RPM → ≤2400 RPM).

 

Motor Types

  1. Permanent Magnet Synchronous Motor (PMSM): Mainstream choice with high power density (30%–50% higher than induction motors), ideal for robotics.
  2. Induction Servo Motor: High-temperature resistance and low cost, suitable for heavy-duty applications (e.g., cranes).

 

Encoder and Feedback

  1. Resolution: 17-bit (131,072 PPR) for most tasks; nanometer-level positioning requires 23-bit (8,388,608 PPR).
  2. Types: Absolute (position memory on power-off), incremental (requires homing), or magnetic (anti-interference).

 

Environmental Adaptability

  1. Protection Rating: IP65+ for outdoor/dusty environments (e.g., AGV motors).
  2. Temperature Range: Industrial-grade: -20°C to +60°C; specialized: -40°C to +85°C.

 

II. Drive Selection Essentials

Motor Compatibility

  1. Current Matching: Drive rated current ≥ motor rated current (e.g., 10A motor → ≥12A drive).
  2. Voltage Compatibility: DC bus voltage must align (e.g., 400V AC → ~700V DC bus).
  3. Power Redundancy: Drive power should exceed motor power by 20%–30% (for transient overloads).

 

Control Modes

  1. Modes: Position/speed/torque modes; multi-axis synchronization requires electronic gearing/cam.
  2. Protocols: EtherCAT (low latency), Profinet (industrial-grade).

 

Dynamic Performance

  1. Bandwidth: Current loop bandwidth ≥1 kHz (≥3 kHz for high-dynamic tasks).
  2. Overload Capability: Sustained 150%–300% rated torque (e.g., palletizing robots).

 

Protection Features

  1. Brake Resistors: Required for frequent starts/stops or high-inertia loads (e.g., elevators).
  2. EMC Design: Integrated filters/shielding for industrial noise resistance.

 

III. Collaborative Optimization

Inertia Adjustment

  1. Use gearboxes to reduce inertia ratio (e.g., planetary gearbox 10:1 → inertia ratio 0.3).
  2. Direct drive (DD motor) eliminates mechanical errors for ultra-high precision.

 

Special Scenarios

  1. Vertical Loads: Brake-equipped motors (e.g., elevator traction) + drive brake signal sync (e.g., SON signal).
  2. High Precision: Cross-coupling algorithms (<5 μm error) and friction compensation.

 

IV. Selection Workflow

  1. Requirements: Define load torque, peak speed, positioning accuracy, and communication protocol.
  2. Simulation: Validate dynamic response (MATLAB/Simulink) and thermal stability under overload.
  3. Testing: Tune PID parameters and inject noise for robustness checks.

 

Summary: Servo selection prioritizes load dynamics, performance, and environmental resilience. ZONCN servo motor and drive kit saves your trouble of selecting 2 times, just consider the Torque, Peak RPM, and Precision.

Post time: Nov-18-2025