Overview
What are AC Servo Motors?
AC servo motors are high-performance brushless motors designed for precise control of angular or linear position, velocity, and acceleration. Unlike standard induction motors, AC servos utilize permanent magnet rotors and feedback devices (encoders) to provide closed-loop control. This allows for rapid response times, high torque-to-inertia ratios, and the ability to maintain position under varying loads. They are the standard for modern automated machinery requiring synchronized movement and high repeatability.
Main Manufacturers
PALM Parts Solution stocks a comprehensive range of AC servo motors from the industry’s leading brands. Our inventory includes:
- Allen-Bradley: High-dynamic performance for the North American market.
- Mitsubishi Electric: Renowned for the MELSERVO series and high-resolution encoder technology.
- Siemens: The global standard for integrated CNC and PLC automation.
- Bosch Rexroth: Specialized in high-torque, heavy-duty motion control.
- Omron & Delta Electronics: Cost-effective, reliable solutions for general-purpose automation.
- Lenze: Engineered for high-efficiency packaging and material handling applications.
Popular Product Families
We supply replacement motors and New-Old-Stock (NOS) components for the following widely-deployed series:
- Allen-Bradley: Kinetix VPL, MPL, and MPM series.
- Mitsubishi: MELSERVO HG-KR, HG-SR, and legacy J4/J2S series.
- Siemens: SIMOTICS S-1FK7, 1FT7, and 1FL6.
- Bosch Rexroth: IndraDyn S (MSK and MSM) series.
- Delta: ASDA-A2 and ASDA-B2 (ECMA motors).
- Omron: 1S and G5 series motors.
Typical Applications
AC servo motors are essential in sectors where precision is non-negotiable. Common applications include:
- CNC Machining: Driving tool changers and axes for milling and turning.
- Packaging Machinery: Synchronizing pick-and-place robots, labeling, and rotary sealing.
- Semiconductor Manufacturing: High-speed wafer handling and precision positioning.
- Printing & Converting: Maintaining web tension and registration at high speeds.
Selection & Replacement Guide
When selecting a replacement AC servo motor, you must match the following specifications exactly to ensure compatibility with your existing drive:
- Frame Size: NEMA or Metric flange dimensions (e.g., 60mm, 100mm).
- Rated Torque & Speed: Ensure the Nm (Newton-meters) and RPM meet the application requirements.
- Encoder Type: Determine if the system uses Incremental, Absolute, or Serial feedback (e.g., Hiperface, EnDat).
- Inertia Matching: Low-inertia motors are for high-speed indexing; medium/high-inertia motors are for heavy loads.
Replacement & Compatibility: If a specific model is discontinued (such as legacy Allen-Bradley 1326AB or Mitsubishi HC series), our technical team can assist in finding modern equivalents or refurbished units that fit your existing mechanical mounting and electrical parameters.
5 products · Siemens
Frequently asked questions
What is the difference between AC and DC servo motors?
The primary difference lies in the power source and commutation method. AC servo motors use alternating current and are brushless, making them more durable and capable of higher speeds and constant torque across a wide range. DC servo motors use brushes that require more maintenance and are typically used for smaller, lower-power applications.
Can I mix different brands of AC servo motors and drives?
Yes, but with significant limitations. While it is possible to use an Allen-Bradley Kinetix motor with a Siemens SINAMICS drive, for example, it requires complex manual configuration of encoder feedback, phasing, and PID loops. Most users prefer 'matched sets' from a single manufacturer to ensure automatic motor recognition and optimal safety integration.
What types of encoders are used in AC servo motors?
Common industrial feedback devices include Incremental Encoders (requiring homing at startup) and Absolute Encoders (retaining position after power loss). Modern high-performance motors, like the Allen-Bradley VPL series or Mitsubishi HG series, often use 22-bit or higher high-resolution absolute encoders for extreme precision.
What are the standard voltage ratings for AC servo motors?
Most industrial AC servo motors are rated for 200-240V (Single or Three Phase) or 400-480V (Three Phase). Choosing the correct voltage is critical to matching your local power grid and the DC bus requirements of your servo drive.
Do I need a separate drive for an AC servo motor?
A servo motor is an 'all-in-one' package including the motor, a feedback device (encoder), and a shaft. A servo drive (or amplifier) is the electronic controller that translates PLC commands into high-frequency pulses to power the motor and monitors the feedback loop. You need both for any motion control application.