From parameters such as torque, speed, and moment of inertia to protection rating and system dynamics, each factor has a significant impact. A proper selection not only improves equipment performance but also optimizes energy consumption and extends the service life of machinery.

Additionally, we will explore what axes are in a servo system, how they work, and how they are revolutionizing industrial process automation. Keep reading to learn more.

Factors to consider when sizing a servo motor

Torque

Torque is one of the most important factors when sizing a servo motor. It defines the motor’s ability to generate the force required to move a load. To size it properly, it is essential to calculate the maximum torque required during the operating cycle, including start, stop, and load conditions. Well-sized torque prevents overloads, avoids premature failures, and ensures efficient operation. Always select a motor with a torque capacity appropriate for your application, allowing a safety margin for possible load peaks.

Speed

Speed determines the motor’s operating rate and directly influences the cycle time and machine productivity. When sizing a servo motor, consider the maximum speed and its variations throughout the cycle. This ensures the motor operates within its limits, avoiding accelerated wear or potential failures.

Inertia

The inertia of the load affects the system’s ability to accelerate and decelerate efficiently. A proper ratio between the motor’s inertia and the load’s inertia allows precise control and stable dynamic response. A mismatch can cause vibrations, instability, and poor control. Therefore, it is crucial to calculate the total system inertia and choose a compatible motor.

Voltage

Voltage is a critical electrical aspect in the selection of servo motors and their controllers. It determines compatibility with the available power supply. Choose a motor with a nominal voltage that aligns with your system requirements to avoid overloads and ensure efficient operation. Correct voltage selection helps maximize energy efficiency and minimize the risk of motor damage.

Current

Current directly influences the motor’s torque and power. When selecting a servo motor, verify that the controller (servo drive) can supply the maximum required current without exceeding its limits. This prevents overheating and ensures safe and stable operation.

Temperature

Thermal management is essential to maintain performance and extend the motor’s service life. During operation, servo motors generate heat, so good thermal dissipation is important. Consider environmental conditions, ventilation, and the system’s thermal efficiency when making your choice.

Power

Power results from the combination of voltage and current and reflects the motor’s ability to perform mechanical work. Select a motor whose power meets your application’s requirements, and ensure that the controller can supply it without creating inefficiencies.

Controller and communication network

The selection of the controller (servo drive) and communication network is key to the overall system performance. The controller translates control system commands into precise motor movements, while the network ensures fast and reliable communication between the controller, motor, and PLC. Good compatibility between these components ensures efficient and precise motion control.

See also: What are electric axes and what are their functions?

Best practices for sizing and selecting servo motors

Following a structured process when sizing and selecting a servo motor is key to ensuring an efficient choice tailored to the specific needs of your application. These are the recommended steps:

• Verify available voltage: Ensure the motor is compatible with your facility’s power supply.
• Define the motion profile: Analyze speed requirements throughout the operating cycle, including acceleration and deceleration.
• Calculate required torque: Consider factors such as acceleration, friction, and any external force acting on the load.
• Evaluate the inertia ratio: Seek a good balance between the load’s inertia and the rotor’s inertia for better control and dynamic response.
• Make a preliminary motor selection: Consider parameters such as voltage, nominal speed, continuous and peak torque, and inertia.
• Determine if a reducer is needed: If your application requires lower speed and higher torque, consider using gear reducers.
• Finalize motor selection: Adjust torque values, inertia, and gear ratios to achieve optimal performance.
• Choose a compatible controller: Verify that it has the appropriate input voltage, required output current, and a control interface that integrates smoothly with your system.

Proper sizing and appropriate servo motor selection are fundamental for achieving efficiency, precision, and reliability in your automation systems. By following these best practices, you can make more informed decisions and improve the overall performance of your project.

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