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How Does a Servo Motor Work?

A typical servo system consists of three main components: A servo motor with one or more feedback devices such as a hall effect sensor, encoder, or resolver, a drive amplifier that powers and controls the motor, and the required cabling between the motor and drive. The system as a whole works by means of a series of embedded control loops.

As the drive powers the motor, the feedback devices monitor the rotor’s velocity and/or position. These signals are sent to the control circuits in the drive, which continuously adjusts the current and voltage being supplied to the motor to instantly correct any errors and ensure that the programmed motions are carried out flawlessly.

There are many types of servo motors, but all share the ability to integrate with feedback devices and respond precisely to position, speed and velocity commands from the drive. This variable and precise motion is essential for use in a wide range of industrial applications: robotics, aerospace, medical imaging, laboratory automation, food & beverage production, metal forming, and many more.

Kollmorgen Servo Motor Key Features

Servo Motor Features

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.

What is a servo motor used for?

Learn how servo motors are used in:

Industrial automation and robotics. Housed and frameless servo motors are advancing the state of the art for factory productivity, surgical precision, energy production and many other endeavors.

CNC machinery and machine tools. Servo motors bring the greatest possible precision and repeatability to shaping, grinding, drilling and other tooling applications.

Aerospace and defense. From surveillance, defense and weapon systems to the commercialization and exploration of space, servo motors are crucial to mission success.

Automotive applications and electric vehicles. Servo systems are improving efficiency and safety from the manufacturing floor to the distribution center and beyond.

Servo systems are also ideal for many other industries and applications. Let’s discuss your specific motion requirements and find the best solution.

Servo Motor Applications

Servo vs. Stepper

Servo motors versus other motor technologies

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.

Get Help With Your Application

Kollmorgen’s collaborative engineering expertise is unmatched in the motion industry. We have been an innovation leader for more than 100 years, and have decades of experience serving each industry that benefits from servo technology. Let us help you engineer the exceptional.

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Servo motors

Servo Motors >

Kollmorgen’s brushless servo motors offer the highest torque/inertia ratio over a broad range of speeds—including high speed capabilities up to 8,000 rpm for standard designs.

AKM2G Servo Motor >

AKM2G represents the latest evolution of the industry-leading AKM motor family. With significant torque increases in the same motor size OEMs can achieve substantial performance improvement without changing the motor mounting or using more machine space.

AKM Motors >

Our best-in-class, high-performance servomotors offer a wide range of mounting, connectivity, feedback and other options. More than 500,000 standard models are available along with co-engineered modifications to suit almost any application…