24 n MOTORS May 2026 www.drivesncontrols.com Choosing the best motors for driving and positioning tasks Electric motors are a vital component in industrial automation. They are found in everything from robotic arms to essential pumps and compressors. Yet, despite their ubiquity, the process of selecting the most suitable motor technology for a given application is far from simple. The market offers a wide range of technologies with different features. For driving tasks which require constant speed and torque, the options include brushed DC motors, AC induction motors, synchronous motors, and synchronous reluctance motors. For positioning tasks, where precision and repeatability are key, the choices include stepper motors, brushless DC (BLDC) motors, asynchronous (induction) motors, synchronous servomotors and linear motors. With such a bewildering range to choose from, time-poor engineers and machinebuilders may be tempted to stick with familiar options. However, this can result in sub-optimal motor and machine performance, higher energy consumption and excessive maintenance requirements, all of which increase the total cost of ownership. A careful, fact-based evaluation that considers the application, technical and commercial criteria is crucial for obtaining the best results. Driving conditions Motor uses can be divided broadly into two categories: drive applications; and controlled motion (positioning) applications. In drive applications, the motor’s primary function is to set and keep a system in continuous motion. Examples include conveyors, pumps and compressors. The focus when choosing these motors is primarily on power output and continuous running efficiency. By contrast, controlled motion applications require dynamic, precise, but often intermittent, movements, such as the positioning of loads. For these applications, accuracy and performance are the primary selection criteria. This can mean a choice between stepper and servomotors. Both are used for precise motion control, but they differ in their control mechanisms and applications. Stepper motors move incrementally and are typically open-loop, while servomotors are closed-loop, using feedback to maintain the desired position and speed. The high dynamics and controllability of servo control loops are extremely useful, but there are times when the pulse, lock and stay characteristics of a stepper are desirable. Extra-low voltage (ELV) drives can offer machine-builders flexibility. They work at 24V or 48V DC and are capable of open- or closed-loop positioning. They effectively bridge the gap between stepper motors and servodrives, offering better performance, improved communications and higher speeds, coupled with an Matching the right motor to your automation task can be a complex exercise. Ben Lloyd, Festo’s product manager for electrical products, explains the key factors that you should consider when trying to choose the best motor for a particular application.
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