With the continuous development of science and technology, motor technology is constantly innovating. Especially nowadays, the industrial field continuously puts forward higher expectations and requirements for the servo characteristics of the motor, so the coreless motor has emerged. In this article, we will introduce the permanent magnets in coreless motors.
Coreless motors are DC permanent magnet servo and control motors, and they can also be classified as micromotors. The coreless motor has outstanding energy-saving characteristics, sensitive and convenient control characteristics, and stable operation characteristics, so it’s very advanced in technology. As a high-efficiency energy conversion device, it represents the development direction of electric motors in many fields.
Coreless motors are DC permanent magnet motors. The main difference between them and ordinary brushed and brushless DC motors is that they use a coreless rotor. The rotor is directly wound by wires without any other structural support. The wires are wound into a cup shape to form the structure of the rotor (as shown below).
Due to the structural changes of the rotor, the operating characteristics of the motor have been greatly improved. It not only has outstanding energy-saving characteristics but more importantly, it has control and drag characteristics that cannot be achieved by iron core motors.
Coreless motors are divided into two types: brushed and brushless. Brushless coreless motors have no iron core in the rotor, and brushless coreless motors have no iron core in the stator. Common coreless motors in the market have diameters Φ4, Φ6, Φ7, Φ8, Φ10, Φ12, Φ15, etc.
Coreless motors have a series of advantages such as high power density, high efficiency, no torque lag, no cogging effect, low starting torque, no radial force between the rotor and stator, a smooth speed curve, low noise, and good heat dissipation effect.
The application of coreless motors has developed rapidly after entering the large industrial and civilian fields from military and high-tech fields for more than ten years, especially in industrially developed countries, where most industries and many products have been involved.
1. The coreless motors can well meet the technical requirements of the follow-up system that needs a fast response, such as the rapid adjustment of the flying direction of the missile, the follow-up control of the high-magnification optical drive, fast automatic focusing, highly sensitive recording and detection equipment, industrial robots, bionic prosthesis, etc.
2. Coreless motors are used for products that require stable and long-lasting drive components, such as various portable instruments, personal equipment, instruments, and equipment for field operations, electric vehicles, etc. The same set of power supplies can extend the power supply time by more than double.
3. Coreless motors are used in various aircraft, including aviation, aerospace, model aircraft, etc. Due to the advantages of coreless motors of lightweight, small size, and low energy consumption, the weight of the aircraft can be reduced to the greatest extent. Coreless motors are also used in a variety of civil electrical appliances and industrial products. Using coreless motors as actuators can improve product quality and performance.
4. Because of the small size of coreless motors, many products with relatively small size requirements use them as power components. For example, toys (toy cars, model airplanes, etc.), massage products (washing brushes, induction instruments, facial massagers, etc.), daily necessities (electric toothbrushes, shampoo brushes, hair straighteners, etc.).
Sintered NdFeB permanent magnets are generally used in coreless motors. They have the characteristics of high remanence, high coercivity, and high energy products. They are the most suitable permanent magnet materials on the market that meet the requirements of coreless motors. Under the same size of motor and winding data, the strength of the magnets directly affects the speed of the motor. Common neodymium magnets suitable for coreless motors are ring-shaped, with a similar performance of N40, N45, etc., and the temperature resistance is about 100°C.
Thank you for reading our article and we hope it can help you to have a better understanding of coreless motors and permanent magnets in coreless motors. If you want to know more about permanent magnets, we would like to advise you to visit Stanford Magnets for more information.
Stanford Magnets is a leading magnet supplier across the world, who has been involved in R&D, manufacturing, and sales of permanent magnets since the 1990s. It provides customers with high-quality rare earth permanent magnetic products, and other non-rare earth permanent magnets at a very competitive price.