What is a Servo Motor?

When selecting a servo motor, look for these key features:

Precise motion. Choose precisely engineered and manufactured motors that work optimally with your choice of high-resolution feedback devices, low-latency fieldbus, high-quality cables and high-performance drive.

High torque and power density. By selecting a motor that provides the continuous and peak torque required for your application in the most compact form factor, such as the AKM2G series, you can build a lighter machine in a smaller footprint — or to increase the performance of an existing machine without redesigning the motor mounting.

Speed control and dynamic response. A servo motor with greater torque density and less inertia will provide greater dynamic response, improving the productivity of your machine. For the smoothest operation, consider a low-cogging motor design paired with a drive that features cogging compensation.

Feedback mechanisms. Understand the advantages of each type of feedback device, including simple, rugged Hall-effect sensors; resolvers that work well in extreme environments; high-resolution optical encoders; and other options. Many motors, such as the AKM and AKM2G, are designed to accommodate most feedback devices with minimal or no modifications.

Motor type. Servo motors are available in a wide range of designs and models, including AC and DC; brushed and brushless; housed, frameless and cartridge; rotary and linear; high, medium and low voltage; washdown and hygienic; submersible; and other options. Kollmorgen engineers can work with you to select the right motor for your application.

Motor selection and sizing. Take advantage of Kollmorgen’s online design tools to achieve the ideal fit and performance characteristics.

Servo versus stepper. Rather than relying on feedback loops, stepper motors move through a fixed number of steps per rotation, which can be controlled by discrete pulses from the stepper drive. This can have advantages and disadvantages, depending on the application. Learn more.

Servo versus induction. Induction motors have historically been used for single-speed applications, such as conveyors. Although modern induction motors and drives can incorporate feedback, they are not usually the best choice for highly dynamic applications requiring the most precise positioning.

Servo motor advantages and disadvantages. Servo systems provide the greatest possible positional accuracy, speed control and dynamic response. They are also highly torque-dense, delivering exceptional torque across the entire speed range. These advantages come at the expense of somewhat greater system cost and complexity compared to motion systems that don’t employ closed-loop control.