For the motor winding temperature, both the resistance method and the direct measurement method are only relative measurements. No method can accurately measure the temperature level at every position of the winding.

In comparison, the average winding temperature measured by the resistance method is more accurate, but the temperature rise of motors of the same specification and the same batch may still vary greatly. This type of problem will be discovered during the type test process of the motor on the one hand, and manifested in the actual application of the motor on the other hand.

For motors with different ventilation structures, the theoretical high temperature is based on theoretical inference and analysis. However, in the actual production and processing of motors, deviation in any link may lead to temperature uncertainty. For example:

(1) The deflection problem of the motor core with radial ventilation ducts is very likely to cause inconsistency in the motor air path, which will cause changes in temperature distribution and have a certain impact on the noise level of the motor.

(2) The randomness of the manufacturing process of the stator and rotor cores, especially for motors with poor punching quality, may lead to differences in temperature rise of products of the same specifications due to inconsistent core iron weight or iron length, and of course also include temperature distribution.

(3) The weight of the motor rotor during dynamic balancing may also lead to differences, especially when the weight is large, or there are casting defects in the rotor, or the heat dissipation effect of the wound rotor winding, etc., which may lead to the final non-compliance.

(4) During the winding varnishing process, unreasonable electrical insulation treatment process or deviation in process execution may lead to poor or inconsistent winding varnishing effect, which directly affects the heat dissipation effect of the motor winding and the temperature rise level. It may also change the theoretical high temperature point, especially for enclosed motors, which are more affected than motors with other structures.

Therefore, the consistency of product performance is a direct reflection of an enterprise's processing quality level. After the level of automation is improved, the human factor will be reduced, the manufacturing will be more consistent with the theory of motor design, and the theoretical simulation will be more consistent with the actual results.