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…

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…

Combining a motor with gears reduces rotational speed while amplifying torque, enabling output characteristics tailored to specific applications. Since motors operate at high speeds on their own, it is common practice to use a gear reduction mechanism to achieve the low-speed, high-torque output required for Industrial equipment. Failure to select an appropriate combination can lead to reduced efficiency and premature failure. The basic process involves clarifying the required torque and rotational speed during the design phase, calculating the reduction ratio, and then determining the type of gear. This article explains everything from the principle of motor operation and power transmission using gears to calculation formulas for reduction ratios and torque, the characteristics and selection criteria for different gear types, and…

Electrical circuit diagram symbols (referred to as “electrical diagram symbols” in JIS) are standards and rules that represent components used in electrical circuits—such as power supplies, resistors, capacitors, transistors, and motors—using standardized graphical representations. In Japan, these are defined as JIS C 0617 under the Japanese Industrial Standards and are harmonized (MOD) with the international standard IEC 60617. In product development and maintenance, designers and manufacturing personnel use circuit diagram symbols as a common language to ensure accurate communication of information. In the design of control circuits for Micromotors, a precise understanding of electrical circuit diagram symbols is crucial because it directly impacts design quality. This article provides an easy-to-understand explanation of electrical circuit symbols, covering everything from the basics…

When installing a motor into equipment, an inappropriate shaft mounting method can result in torque transmission loss due to slippage and abnormal vibration. In the worst-case scenario, there is a risk of accidents caused by parts falling off or equipment damage. In medical equipment and industrial precision equipment, even the slightest mounting defect can affect product performance and safety; therefore, it is essential to select the correct mounting method based on the shaft shape. Three main types of motor shafts are used: D-cut shafts, round shafts, and keyway shafts. Each differs in the fastening methods that can be applied, the torque they can transmit, and the difficulty of machining. This article explains the characteristics of each shaft shape and typical…

DC motors are motors that use a DC power supply to generate rotational motion.They convert electrical energy into mechanical energy and are used in a wide range of fields, from industrial equipment to medical equipment and automotive electrical components. DC motors come in brushed and Brushless DC Motors varieties, each with different structures and characteristics. Brushed DC motors require no drive circuit and are low-cost, while Brushless DC Motors offer a long service life and excellent quiet operation; they can be selected based on the application and required performance. Furthermore, a clear understanding of the differences between DC motors and AC motors—which operate on alternating current—will help you with motor selection for your application. While DC motors offer greater flexibility…

In manufacturing equipment and industrial equipment, couplings (shaft couplings) are used to accurately transmit power from a motor to a driven shaft. A coupling is a mechanical component that connects the drive shaft and the driven shaft, serving functions such as absorbing mounting misalignment and dampening vibrations. However, there are several types of couplings—including jaw-type, disc-type, and bellows-type—and selection must be based on the specific application and required characteristics. This article provides a systematic explanation ranging from the basic functions of couplings to their main types and characteristics, as well as key points for selection. It also summarizes how to pair couplings with motors—essential knowledge for maximizing coupling performance during motor selection.   Supervised by: C.I. TAKIRON Corporation Electronic Devices…

Moment of inertia is a physical quantity that indicates how easily a rotating object can be set in motion or brought to a stop, and it is an essential factor in motor design calculations. During motor selection, it is necessary to correctly calculate the load’s moment of inertia and estimate the required torque and acceleration/deceleration performance. If the moment of inertia is estimated incorrectly, depending on the motor type and operating conditions, this can lead to overshoot or undershoot during startup and stopping, control instability, or even operational failure. In this article, we will explain step-by-step everything from the basic definition of moment of inertia and its relationship to torque, to calculation formulas for typical motor configurations, and key points…

One of the most critical factors determining a motor’s performance is its “winding.” Windings consist of conductors—such as copper or aluminum wire—wound into coils. When an electric current flows through them, they generate a magnetic field. Through interaction with other magnetic fields (such as those from permanent magnets or other windings), they produce the rotational force that drives the motor, making them the heart of the motor.In motors used across a wide range of fields—from industrial motors to medical equipment, optical equipment, and security equipment—the materials, types, winding methods, and design of the windings directly impact performance, efficiency, durability, and reliability. This article systematically explains the knowledge that B2B engineers need to know, ranging from the basic principles of motor…

In product and mechanical design, the concept of the “safety factor” is crucial for preventing component breakage and failure. The safety factor is an indicator that specifies the margin of safety to be maintained relative to the actual load applied to materials or components, serving as a criterion for ensuring product reliability. When performing motor selection, setting an appropriate safety factor for the anticipated load is essential for extending the lifespan of the product and reducing the risk of failure. In this article, we provide an easy-to-understand explanation for beginners, covering everything from the basic definition of the safety factor to calculation methods, how to determine it in practice, and guideline values for mechanical design.   Supervised by: C.I. TAKIRON…