
In this column, engineers from C.I. Takiron. share their expert knowledge on micromotors (coreless motors, brushless motors, and gearheads). We hope you find this information useful when selecting motors for a wide range of applications, including medical devices, industrial tools, and optical equipment.
This guide provides a detailed explanation of the technical considerations for motor selection, aimed at product development engineers and design professionals. It addresses common questions such as, “I don’t know which motor to choose,” and “I want to understand the difference between coreless and brushless motors.”

In the manufacturing industry, against a backdrop of labor shortages and a decline in the number of skilled workers, there is a growing need to address labor-saving measures and automation. Among these solutions, “collaborative robots”—designed to work alongside humans in the same workspace—are attracting particular attention. They are easy to integrate into existing processes while ensuring safety, and they help support high-mix, low-volume production and reduce the workload on workers. On the other hand, there are several key points to verify before implementation, such as speed, payload capacity, and safety measures. In this article, we provide an easy-to-understand explanation of how collaborative robots work, how they differ from Industrial robots, their advantages and disadvantages, their main applications, and…

Myoelectric prosthetic hands are devices that read electromyographic (EMG) signals generated by muscle contractions to drive motors and move the fingers and hand. Since they are worn on the body, the motors must meet a wide range of performance requirements—including not only the necessary gripping force but also compact and lightweight design, responsiveness, low power consumption, low heat generation, and quiet operation. Focusing on only certain performance aspects can lead to increased weight, reduced operability, and shorter operating times. In this article, we will first outline how myoelectric prosthetic hands work, then explain the performance requirements for motors, key selection criteria, and the characteristics of Coreless motors. Supervised by: C.I. TAKIRON Corporation Electronic Devices Sales Group This article…

Robotic hands are required to do more than simply grasp and release objects; they must also open and close fingers, bend and extend joints, and make fine adjustments to gripping force. In electrically powered systems, if the motor’s size, torque, and responsiveness are not appropriate, the robotic hand may fail to achieve sufficient gripping force or its movements may become jerky. Since the performance priorities differ for industrial grippers, multi-finger hands, and prosthetic hands, it is crucial to select a motor tailored to the specific application and mechanical design. This article explains the role of motors in robotic hands, the performance requirements for each type, key selection criteria, and the characteristics of Coreless motors. Supervised by: C.I. TAKIRON Corporation…

Motor carbon brushes are components that transmit electric current through sliding contact with the commutator (or slip ring); in DC motors, they work in conjunction with the commutator to maintain rotation. They are used in a wide range of equipment, from industrial motors to power tools. If carbon brushes wear out or commutation becomes unstable, it can lead to sparking or damage to the commutator, making them critical from the perspective of maintenance and downtime risks. Carbon brush materials include electrographite, natural graphite, and metal graphite, among others, and selecting the appropriate material based on the application and operating conditions is essential. Understanding how to assess lifespan and replacement timing based on brush wear, as well as how to diagnose…

While a motor is rotating, the torque it outputs is not entirely constant. Instantaneous torque undergoes slight periodic fluctuations, manifesting as variations in rotational force. These periodic torque fluctuations are known as “torque ripple.” Significant torque ripple adversely affects equipment performance, leading to vibration, noise, reduced positioning accuracy, and degraded controllability.This is a technical challenge that cannot be ignored, particularly in fields where smooth operation and precision are directly linked to quality, such as medical equipment, optical equipment, and industrial robots. In this article, after clarifying the basic meaning of torque ripple and its difference from cogging torque, we will explain the main causes of its occurrence and methods for reducing it from the perspectives of design, control, and motor…

The ability to accurately measure and control a motor’s rotational speed is critical, as it directly impacts equipment performance and stable operation (required specifications). “I want to know the formula for calculating rotational speed.” “I want to understand how voltage and torque affect rotational speed” “I want to explore methods for achieving precise speed control” To address these technical challenges, this article provides a technically grounded explanation—ranging from the basic calculation formula for DC motor rotational speed to the factors affecting rotational speed, how to interpret T-N characteristics (torque characteristics) and how to use PWM control and feedback control for practical speed control. We provide information that will be useful to engineers in fields where reducing speed fluctuations and maintaining…

As medical equipment continues to become smaller and more precise, the role played by the motors that drive it is growing year by year. Compact motors are now incorporated into many devices used in medical settings—such as dental treatment units, endoscopes, electronic pipettes, and surgical assistance robots—and serve as core components that support the functionality and performance of these devices.Motors incorporated into medical equipment tend to be subject to higher performance standards than general-purpose industrial motors. To achieve the operational precision required by the equipment, it is essential to select the optimal motor for the specific application—one that offers smooth rotation, low vibration, a long service life, and a compact design. In this article, we will explain the typical applications…

Inverters are power conversion devices used across a wide range of fields, from home appliances to Industrial equipment. They are recognized as a core technology supporting both daily life and industrial operations, enabling energy saving operation of air conditioners and refrigerators, motor control in factories, and smooth acceleration and deceleration in elevators. However, there are few opportunities to systematically understand the internal structure of these devices or how they interact with motors.In this article, we will explain everything step by step—from the basic definition and mechanism of inverters to their role in motor control, real-world application examples, and key points to keep in mind during implementation. We have organized the knowledge essential for design decisions for engineers involved in motor…

The number of poles in a motor is a basic specification indicating the number of magnetic poles formed inside the motor, and it is a parameter that influences rotational speed and torque characteristics. In the design and procurement of Micromotors, questions often arise regarding whether to choose a 2-pole or 4-pole motor, and how an increase in the number of poles affects performance.The number of poles is not a value determined in isolation; rather, the optimal solution is determined by balancing speed, torque, size, cost, and the technical requirements of each specific application. In this article, we will systematically cover the basics of motor pole count, its relationship to speed, and the approach to motor selection based on application. The…

In fields such as industrial equipment, medical equipment, and robotics, designs that balance miniaturization with the necessary torque are critical to product performance. Concerns such as “Can we increase the torque a little more while keeping the size the same?” and “We want to make the device smaller, but we’re worried about whether it can withstand the load” are recurring design challenges faced in development environments.In this article, we will provide a comprehensive explanation, covering everything from the basic mechanisms of compact high-torque Torque motors to typical methods for increasing torque, their main applications, and key points to consider during the selection process. We have also compiled frequently asked questions from the design field in a Q&A format. We hope…