A comprehensive analysis of what a permanent magnet motor is

A permanent magnet motor is a small AC motor that uses permanent magnets to generate a magnetic field. Permanent magnet motors have the function of both electric motors and generators. Compared with excitation motors, permanent magnet motors have the advantages of simple structure, reliable operation, energy saving, material saving, light weight and high efficiency.

There are three common types of permanent magnet motors:

1. Surface-mounted permanent magnet motor.

Surface-mounted permanent magnet motor refers to a permanent magnet motor with a salient pole synchronous rotor magnetic circuit structure. Its manufacturing process is similar to that of general salient pole synchronous motors, and it is a relatively mature type of permanent magnet motor.

2. Embedded permanent magnet motor.

Embedded permanent magnet motor refers to a permanent magnet motor with a rotor magnetic circuit structure of hidden electrode synchronization. Compared with the surface-mounted permanent magnet motor, the rotor punching of the embedded permanent magnet motor has high mechanical strength, and the rotor punching and rotating shaft of the ordinary induction motor can be directly used, which has strong processing adaptability. In addition, the magnetic field of the embedded permanent magnet motor is easy to adjust, which is conducive to the effective control of the air gap magnetic field of the motor and improves the speed regulation performance of the motor.

3. Claw pole permanent magnet motor.

A claw pole permanent magnet motor is a permanent magnet motor that uses two or more magnetic rotors to rotate in opposite directions to generate a rotating magnetic field. The claw pole permanent magnet motor has the advantages of simple structure, low cost and high reliability, but it is difficult to adjust the magnetic field and has poor speed regulation performance.

The excitation method of using DC current to generate the main pole magnetic field is called electric excitation: if the current excitation is replaced by a permanent magnet, the main pole field is generated. This kind of motor is called a permanent magnet motor.

Permanent magnet motors have the advantages of light weight, small size, high efficiency and reliable operation. In many cases, brushless can be realized, so it is mostly used in small and micro motors. When the variable frequency power supply is used, the permanent magnet motor can also be used for the speed control transmission system.

With the continuous improvement and improvement of the performance of permanent magnet materials, permanent magnet motors have been widely used in various fields such as household appliances, medical equipment, automobiles, aviation and defense.

The disadvantage of permanent magnet motors is that, if used improperly, when working at too high or too low temperatures, under the action of the armature reaction generated by the impulse current, or under severe mechanical vibration. There is a possibility of irreversible demagnetization. The performance of the motor is reduced or even unusable.

Therefore. When using a permanent magnet motor. Special attention should be paid to it.

Permanent magnet motor refers to a DC AC synchronous motor with a permanent magnet and a stator coil, or a permanent magnet motor with an internal rotor and an external rotor.

The permanent magnet motor is mainly composed of various components such as rotor, end cover and stator. The stator structure of the permanent magnet synchronous motor is very similar to that of an ordinary induction motor, and the biggest difference between the rotor structure and the asynchronous motor is that a high-quality permanent magnet pole is placed on the rotor.

The difference between permanent magnet motor and ordinary motor is: 1. Magnetic field properties. After the permanent magnet motor is made, it does not need external energy to maintain its magnetic field; Ordinary motors require current to be fed in order to have a magnetic field.

2. Rotor structure. The rotor of the permanent magnet motor is provided with a permanent magnet pole; An excitation coil is installed on the rotor of an ordinary motor. 3. Applicable occasions.

Permanent magnet motors are usually used in low-power applications; Ordinary motors, especially excitation motors, are often used in high-power applications. Features: Permanent magnet motor is a form of rectangular pulse wave, current sine wave current, hybrid permanent magnet motor.

Simple structure, high reliability and high efficiency. Ordinary motors have fast response, large starting torque, and can provide rated torque from zero speed to rated speed. Introduction to Permanent Magnet Motors:

The permanent magnet DC motor is also composed of stator poles, rotors, brushes, shells, etc., and the stator poles are made of permanent magnets (permanent magnets), with ferrite, alnico, neodymium iron boron and other materials. According to its structural form, it can be divided into cylindrical type and tile type. Most of the electricity used in VCRs is cylindrical magnets, while most of the motors used in power tools and automotive appliances use special block magnets.

The rotor is generally made of silicon steel sheets, which has fewer slots than the rotor of electromagnetic DC motors. Most of the low-power motors used in VCRs are 3-slot, and the higher-end ones are 5-slot or 7-slot. The enameled wire is wound between two slots in the rotor core (three slots have three windings), and its joints are welded to the metal sheet of the commutator.

Brushes are conductive parts that connect the power supply to the rotor windings, and have both conductive and wear-resistant properties. The brushes of the permanent magnet motor use single metal sheets or metal graphite brushes, and electroized graphite brushes. The permanent magnet DC motor used in the VCR adopts an electronic speed stabilization circuit or a centrifugal speed stabilization device.

Ordinary motor: motor refers to an electromagnetic device that realizes the conversion or transmission of electrical energy according to the law of electromagnetic induction, and its main role is to use mechanical energy to convert into electrical energy and generate driving torque, as a power source for electrical appliances or various machinery. At present, the most commonly used is to use thermal energy, hydro energy and other power to drive the rotor of the generator to generate electricity, with the maturity of wind power generation technology, wind power has slowly entered our lives.

Working power supply types: can be divided into DC motor and AC motor, DC motor is a motor that relies on DC working voltage to run, widely used in cassette recorders, video recorders, DVD players, electric shavers, hair dryers, electronic watches, toys, etc.

Answer 1) High efficiency: After embedding the permanent magnet material on the rotor, the rotor and the stator magnetic field run synchronously during normal operation, and the rotor winding has no inductive current, and there is no rotor resistance and hysteresis loss, which improves the efficiency of the motor.

2) High power factor: there is no inductive current excitation in the rotor of the permanent magnet synchronous motor, the stator winding presents a resistive load, and the power factor of the motor is close to 1, which reduces the stator current and improves the efficiency of the motor. At the same time, the improvement of power factor improves the quality factor of power grid, reduces the loss of transmission and transformation lines, and the transmission and transformation capacity can also be reduced, saving power grid investment.

3) Large starting torque: In equipment that requires large starting torque (such as oilfield pumping motors), smaller capacity permanent magnet motors can be used to replace larger capacity Y series motors. If the 37 kW permanent magnet synchronous motor replaces the 45 kW 55 kW Y-series motor, the phenomenon of "big horse-drawn trolley" is better solved, the equipment investment cost is saved, and the operation efficiency of the system is improved.

4) Good force index: When the Y series motor works under the load of 60, the efficiency decreases by 15, the power factor decreases by 30, and the power index decreases by 40; However, the efficiency and power factor of the permanent magnet synchronous motor are reduced very little, and when the motor is only 20 loads, its force index is still more than 80 at full load.

5) Low temperature rise: there is no resistance loss in the rotor winding, and there is almost no reactive current in the stator winding, so the temperature rise of the motor is low.

6) Small size, light weight, less consumables: the volume, weight and materials used of the permanent magnet synchronous motor of the same capacity can be reduced by about 30.

7) It can be large gap, which is convenient for the formation of a new type of magnetic circuit.

8) The armature reaction is small and the anti-overload capacity is strong.