Custom High Torque Permanent Magnet Motors Manufacturers

In a high-torque permanent magnet DC motor, how do the magnetic fields generated by permanent magnets and the magnetic fields generated by armature current interact to generate high torque? ​

Overview of the basic structure and principle of permanent magnet DC motors​
Before we delve into the interaction of magnetic fields, let's first understand the basic structure of High Torque PMDC Motor. Permanent Magnet Motors are mainly composed of permanent magnets, armatures, brushes and commutators. As an important part of the motor, the permanent magnet provides a constant main magnetic field to lay the foundation for the operation of the motor. The armature is one of the core components of the motor. It consists of an iron core and a winding. When current is passed through the armature winding, an armature magnetic field is generated. The brushes and commutator cooperate with each other to ensure that the current direction in the armature winding can be changed in time during the operation of the motor, thereby ensuring that the motor rotates continuously and stably. ​
In principle, the operation of permanent magnet DC motors is based on the law of electromagnetic induction and Ampere's force law. When current passes through the armature winding, according to Ampere's force law, the current-carrying conductor will be acted upon by force in the magnetic field. The direction of this force is determined by the left-hand rule, and its magnitude is proportional to the magnetic field strength, current size, and effective length of the conductor in the magnetic field. In a permanent magnet DC motor, the main magnetic field generated by the permanent magnet interacts with the magnetic field generated by the armature current to generate electromagnetic torque, drive the armature to rotate, and then drive the load to work. This process is like a carefully choreographed dance, with the two magnetic fields working together to complete the conversion and transfer of energy. ​
Magnetic field characteristics generated by permanent magnets​

The magnetic field generated by permanent magnets has unique characteristics. First, the magnetic field strength of permanent magnets is relatively stable, thanks to their special internal magnetic domain structure. In permanent magnet materials, magnetic domains are oriented and arranged during the manufacturing process, forming a relatively stable macroscopic magnetic field. This stability enables permanent magnets to provide a reliable basic magnetic field for the motor, ensuring that the motor can operate normally under different working conditions. ​
The magnetic field distribution of permanent magnets also has a certain regularity. In common permanent magnet DC motors, permanent magnets are usually installed in the stator part of the motor, and the magnetic field they generate is distributed radially. This distribution method helps to form a more uniform magnetic field environment inside the motor, so that the armature winding can cut the magnetic lines of force more evenly during rotation, thereby generating a more stable induced electromotive force and electromagnetic torque. ​
The magnetic field characteristics of permanent magnets are also closely related to their materials. Common permanent magnet materials include neodymium iron boron and ferrite. Different materials have different magnetic properties. For example, neodymium iron boron permanent magnets have the characteristics of high remanence, high coercive force and high magnetic energy product, and can generate a strong magnetic field, which is suitable for occasions with high requirements for motor performance; while ferrite permanent magnets have the advantages of low cost and high Curie temperature, and are widely used in some cost-sensitive applications. As a professional motor manufacturer, Hangzhou Hengbai Reducer Co., Ltd. strictly controls the selection of permanent magnet materials and cooperates with screened and audited raw material suppliers to ensure that the selected permanent magnet materials are of high quality, providing a solid guarantee for the performance of high-torque permanent magnet DC motors. ​
Magnetic field characteristics generated by armature current​
When current is passed through the armature winding, an armature magnetic field is generated. The characteristics of the armature magnetic field are closely related to the structure of the armature winding and the magnitude and direction of the current passed through. ​
The armature winding has various structures, the most common of which are lap winding and wave winding. Different winding structures will affect the distribution of the armature magnetic field and the performance of the motor. For example, the advantage of lap winding is that the winding ends are shorter, which saves materials and is often used in general DC motors; wave winding is suitable for occasions where a large number of series conductors are required, which can increase the electromotive force and power of the motor. ​
The magnitude and direction of the current passed through the armature winding determine the strength and direction of the armature magnetic field. According to Ampere's circuit law, the greater the current, the stronger the magnetic field intensity generated. Moreover, through the action of brushes and commutators, the direction of the current in the armature winding will change periodically as the armature rotates, thereby changing the direction of the armature magnetic field. This periodic change is one of the key factors to ensure that the motor can rotate continuously. ​
The armature magnetic field will also affect the main magnetic field generated by the permanent magnet, which is called armature reaction. The armature reaction will distort the main magnetic field, resulting in uneven distribution of the air gap magnetic field of the motor. To a certain extent, armature reaction will affect the performance of the motor, such as causing the electromagnetic torque of the motor to fluctuate and the commutation conditions to deteriorate. Therefore, in the design and operation of the motor, the influence of armature reaction needs to be fully considered, and corresponding measures need to be taken to compensate and optimize it. ​
Mechanism of high torque generated by magnetic field interaction ​
Generation and action of electromagnetic force ​
When the magnetic field generated by the permanent magnet interacts with the magnetic field generated by the armature current, electromagnetic force is generated. These electromagnetic forces act on the armature winding to form electromagnetic torque. Electromagnetic torque is the key to the output power of the motor, and its size directly affects the torque performance of the motor. During the operation of the motor, the electromagnetic forces exerted on many armature windings work together to form a total electromagnetic torque, which drives the armature to rotate and then drives the load to work. In some industrial applications, high-torque permanent magnet DC motors need to drive large mechanical equipment. The strong electromagnetic torque can ensure that the motor can easily overcome the resistance of the load and achieve efficient and stable operation. ​
Contribution of reluctance torque ​
In addition to the torque generated by electromagnetic force, in high-torque permanent magnet DC motors, reluctance torque also makes an important contribution to the total torque. Reluctance torque is caused by the unevenness of the air gap magnetic field of the motor and the change of reluctance caused by the armature reaction. ​
When the armature rotates, the relative position between the armature magnetic field and the permanent magnet magnetic field changes continuously, causing the reluctance in the motor air gap to change periodically. According to the principle of minimum reluctance, the motor always tends to operate at the position where the reluctance is minimum, thus generating reluctance torque. The magnitude of the reluctance torque is related to factors such as the structural parameters, magnetic field distribution and operating state of the motor. In some specially designed high-torque permanent magnet DC motors, by optimizing the magnetic circuit structure of the motor and increasing the amplitude of the reluctance change, the proportion of reluctance torque in the total torque is increased, further improving the torque performance of the motor. ​
Cooperative optimization of magnetic field interaction ​
In order to achieve high torque output, it is necessary to coordinately optimize the interaction between the permanent magnet magnetic field and the armature current magnetic field. In the motor design stage, engineers will determine the shape, size, material of the permanent magnet and the number of turns, wire diameter, winding form and other parameters of the armature winding through precise calculation and simulation, so that the two magnetic fields can interact with each other in the best state.​
By rationally selecting the material and size of the permanent magnet, the strength and distribution of the permanent magnet magnetic field can be adjusted to better match the armature magnetic field. At the same time, optimizing the design of the armature winding can control the size and distribution of the armature current, thereby adjusting the characteristics of the armature magnetic field. In addition, some advanced control strategies, such as vector control and direct torque control, can be used to monitor and adjust the operating status of the motor in real time to ensure that the two magnetic fields always maintain a good cooperative working state to generate the maximum torque. Hangzhou Hengbai Reducer Co., Ltd. has professional technical personnel and a scientific management system. In the process of motor design and production, it fully utilizes advanced technologies and concepts to conduct in-depth research and optimization on magnetic field interaction, and is committed to providing customers with high-performance high-torque permanent magnet DC motors. ​
Factors affecting magnetic field interaction and torque output ​
Influence of motor structural parameters ​
The structural parameters of the motor have a significant impact on magnetic field interaction and torque output. For example, the size and shape of the permanent magnet directly affect the strength and distribution of the magnetic field it generates. Larger permanent magnets usually produce stronger magnetic fields, but they also increase the size and cost of the motor. Therefore, a trade-off needs to be made between motor performance and cost.​
The structural parameters of the armature, such as the length, diameter, number of slots of the armature core and the number of turns of the armature winding, will also affect the magnetic field interaction. The length and diameter of the armature core determine the effective length and spatial layout of the armature winding, which in turn affects the magnitude of the electromagnetic force. The choice of the number of slots will affect the distribution of the armature magnetic field and the cogging torque of the motor. The more turns of the armature winding, the stronger the magnetic field strength generated when the same current is passed, but it will also increase the resistance of the winding, resulting in increased copper loss. ​
The influence of current magnitude and direction ​
The magnitude and direction of the armature current are key factors affecting the magnetic field interaction and torque output. As mentioned above, according to Ampere's force law, the larger the current, the greater the electromagnetic force generated, and thus the greater the electromagnetic torque. However, excessive current will cause serious heating of the motor, increase copper loss, reduce the efficiency of the motor, and may even damage the motor. Therefore, it is necessary to reasonably control the magnitude of the armature current according to the rated parameters and load requirements of the motor. ​
The change of current direction is achieved through brushes and commutators, which ensure that the interaction between the armature magnetic field and the permanent magnet magnetic field can always generate electromagnetic torque to drive the armature to rotate. If there is a problem with the switching of the current direction, such as poor contact between the brush and the commutator, resulting in untimely or inaccurate current commutation, the electromagnetic torque will decrease, and even cause the motor to vibrate and increase noise. ​
The influence of temperature and material property changes ​
The motor will generate heat during operation, causing the temperature to rise. Temperature changes will affect the material properties of the permanent magnet and the armature winding, and then affect the magnetic field interaction and torque output. ​
For permanent magnets, temperature increases may cause their magnetic properties to decrease, that is, the magnetic field strength is weakened. Different permanent magnet materials have different sensitivities to temperature. For example, the magnetic properties of neodymium iron boron permanent magnets decrease significantly in high temperature environments. This requires that the temperature characteristics of permanent magnets be fully considered during the design and use of the motor, and effective heat dissipation measures should be taken, such as installing cooling fans and heat sinks, to ensure that the permanent magnets work within a suitable temperature range. ​
The resistance of the armature winding will also increase with the increase in temperature, which will increase the copper loss generated by the current in the winding, further reducing the efficiency of the motor. At the same time, temperature changes may also affect the insulation performance of the winding, and there is a risk of insulation damage. Therefore, temperature monitoring and control of the motor are crucial. Reasonable cooling system design and temperature protection measures can ensure stable operation of the motor under different working conditions and maintain good magnetic field interaction and torque output performance.