Why test inductance for DC brushless motor stator?

AIP shares with you the" Why test inductance for DC brushless motor stator?".

August 15, 2023

Why test inductance for DC brushless motor stator?

DC brushless motor consists of a stator and rotor, The stator core structure is different: mainly includes bar type, splicing block type, and other forms, and there are straight winding, inner winding, flying fork, and other ways of winding. Therefore, in the production process, the same will cause damage to the enameled wire, thus causing potential quality hazards;

In order to control the quality of products, compared with traditional AC motors, DC brushless motors also need to carry out AC Hi-pot, insulation resistance, coil resistance, surge, phase sequence/rotation, and other tests on the stator, in these Test items on the basis of these test items, it is generally recommended to add coil inductance test to the stator, which can realize one-stop inspection, and at the same time, it can be docked with the automated production system, and the test display interface is as follows:

Test interface - AIP

Inductance is a parameter characterizing the performance of a current-carrying coil and its surrounding magnetically conductive material, in the structure of the DC brushless motor, three-phase coils are distributed in space with a difference of 120 ° electrical angle form, three-phase coils are fed with current, the current flows through the coils, the coils are not only self-inductive, the coils have mutual inductance with each other and the size of the self-inductance and mutual inductance with the different rotor position and change.

Therefore, the size of the inductance parameter of the DC brushless motor not only directly affects the steady-state performance such as the average torque of the system, but also has an impact on the dynamic performance of the motor such as phase-change fluctuation, start-up time, and mechanical characteristics.

Due to the existence of motor inductance, the motor current fluctuates during the phase change process, thus causing fluctuations in the motor torque. For high-speed DC brushless motors, if the motor inductance is too large, it will cause the phase change time of the motor to account for too large a proportion of the motor's operation, and even cause the motor's phase change to fail.

In finished motors, the inductance of the motor is related to a number of components such as the stator coil, iron core, rotor magnet, and so on. However, from the point of view of product quality control, it is generally required that the inductance index of the stator itself needs to be controlled in the stator link, so as to avoid the flow of defective products into the later process, which may cause more damages.

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