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Main Properties of Injection Molded Permanent Magnetic Materials

The permanent magnetic materials produced by injection molding have been used in many fields due to their superior magnetic properties. Below is a brief introduction to the main performance of permanent magnetic materials.

Remanence induction strength of permanent magnetic materials

It refers to the magnetic induction strength of permanent magnetic materials when the external magnetic field is zero after the permanent magnetic materials are magnetized to saturation. The index data is directly related to the gap magnetic flux density in the motor. The higher the magnetic induction value, the higher the gap magnetic flux density in the motor.

The main indicators such as the torque constant and the counter-electromotive force coefficient of the motor will reach the best value. In this way, the relationship between the values of the electric load and the magnetic load of the permanent magnetic material motor can be most reasonable, and the efficiency can also reach the best.

Coercive force Hcb of permanent magnetic materials

It refers to the reverse magnetic field strength required when the residual magnetic induction strength Br decreases to zero under the condition of saturated magnetization of permanent magnetic materials. This index is related to the demagnetization ability of the motor, i.e. overload multiple and gap magnetic flux density.

The larger the Hc value, the stronger the motor's ability to resist demagnetization. In addition, the larger the overload multiple of the magnetic material, the stronger the adaptability to the dynamic working environment of strong demagnetization. At the same time, the gap magnetic flux density of the motor will also be improved.

Maximum magnetic energy product BHmax of permanent magnetic materials

It refers to the maximum value of the magnetic field energy provided by permanent magnetic materials to the external magnetic circuit. This index is directly related to the amount of permanent magnetic materials used in the motor.

The larger the BHmax, the larger the magnetic field energy that permanent magnetic materials can provide to the external magnetic circuit, which means that the less permanent magnetic materials are used in the motor under the same power conditions.

Intrinsic coercive force Hci of permanent magnetic materials

This index refers to the magnetic field strength value when the residual magnetization strength M decreases to zero. The Hcb value on the demagnetization curve only indicates that the permanent magnet cannot provide energy to the external magnetic circuit at this time, but it does not mean that the permanent magnet itself has no energy.

However, when M = 0, the corresponding Hci value indicates that the permanent magnet has truly demagnetized and has no magnetic field energy storage. Although Hci is not directly related to the working point of the motor, it is the true coercive force of the permanent magnetic material.

It represents the magnetic field energy and demagnetization resistance of permanent magnetic materials. The intrinsic coercive force is closely related to the temperature stability of permanent magnetic materials. The higher the intrinsic coercive force, the higher the working temperature of permanent magnetic materials.

Temperature coefficient α of permanent magnetic materials

Temperature is one of the main factors affecting the magnetic properties of permanent magnetic materials. The percentage of reversible change in magnetic properties of magnetic materials when the temperature changes by 1℃ is called the temperature coefficient of magnetic materials. The temperature coefficient can be divided into remanence induction temperature coefficient and coercive force temperature coefficient.

This index has a great impact on the performance stability of the motor. When the motor runs from a cold state to a hot state, the higher the temperature coefficient of the permanent magnetic material, the greater the change in this index. It directly limits the working temperature range of the motor and indirectly affects the power-to-volume ratio of the motor.