For different series of motors, the design of the temperature rise margin is different; for the same series of motors, it could be due to factors such as power, installation, commonality of parts and components, etc., there will be a very tight physical space. The increase in motor temperature is usually only found during the type test and the operation process, leading to non-compliance of the motor temperature. The reasons can be verified and analyzed from the aspects of loss and ventilation.

When the stator current and the stator copper loss are large, this will lead to a high temperature rise of the motor, and the rotor copper loss and the iron core will also directly affect the increase in motor temperature. For ventilation losses, in most cases, it is necessary to reduce the temperature increase. The related losses in the design process will be balanced in the overall effect, but also through the balance of the use of materials for the overall cost arrangement.

In motorized products, the air path has a significant impact on the temperature rise of the motor. The motor fan, the air cover, the aluminum-cast rotor air blades, the internal fan, the final dimensions of the stator winding, the air path of the motor with radial ventilation channels, and the alignment of the stator and rotor affect the ventilation effect of the motor.

The wind pressure and air volume generated by the rotor fan are limited by the structure and efficiency of the motor. Keeping the wind path smooth and reducing the wind resistance can increase the wind volume; adjusting the proportion of the wind resistance in the parallel wind path can reasonably distribute the wind volume. Appropriately adjusting the shape, position, and size of the ventilation components to avoid local circulation or ineffective air flow circulation can effectively reduce the temperature rise of the motor.

A large portion of the heat from the stator winding of a protective motor is dissipated from the end. Centrifugal fans should be located as close as possible to the center of the stator winding ends so that the cooling air can effectively cool the winding ends. The blades of the aluminum-cast rotor fan should have an appropriate radial offset from the stator winding end, and a very narrow air path will reduce the amount of air on the final surface of the winding. For dispersed-embedded stator windings, especially the effect in high-speed motors is more obvious.

For a motor with radial ventilation channels, if the length of each section of the core does not match the design, and the processing errors in the seat, rotor shaft, end covers, and other axial dimensions are too large, it will cause the stator and rotor core ventilation slots to be misaligned with the rotor air duct spacer, making it difficult for the air flow to enter the stator ventilation slots. The distortion of the radial ventilation channels during the processing of the stator and rotor cores has a particularly serious impact on the temperature rise of the motor.

In addition to the factors of the stator and rotor cores and windings, the cavity of the seat, the shape and size of the heat dissipation window, as well as their interactions with each other, also have a significant impact on the motor air circuit.

Wind is one of the biggest factors affecting the performance of motorized products, especially for the temperature rise of the motor and the noise performance which is more obvious. But precisely in the design and control of the wind path, most manufacturers are not very perceptive. For example, directly migrating the casting chassis program to the box-type chassis program, although the mechanical coordination dimensions are compliant, does not necessarily guarantee the consistency of the wind path between them. Research in this area needs to be further deepened.