In the era of trams, how should we evaluate whether the motor is good or bad?
Many people may think that the type of motor determines the quality of the motor.
As the two most used motors at present - permanent magnet synchronous motor and AC asynchronous motor, although the outside world has different opinions on the two types of motors, in fact, both have their own advantages, and they cannot be evaluated purely by type.
Some people think that the quality of a motor should be related to its performance parameters, such as acceleration, top speed and power consumption. No matter what kind of motor it is, as long as these three parameters are higher, the motor will be better.
But in fact, extreme speed, acceleration, and power consumption cannot determine the quality of the motor, because behind them, there is another core element that limits their upper limit, which prevents the motor from making more extreme performance.
The core of really evaluating the quality of the motor is heat dissipation. Whether it is the acceleration capability of the electric car, the long-lasting extreme speed performance, or the economical power consumption level, it is inseparable from the support of heat dissipation. Heat dissipation determines both the upper limit and the lower limit of the motor.
For example, the permanent magnet synchronous motor is particularly dependent on heat dissipation because its rotor uses permanent magnet materials. At high temperatures, the permanent magnets will have the risk of complete demagnetization and are irreversible.
As for the AC asynchronous motor, because the rotor uses a traditional coil winding structure, it will emit a lot of heat when it is running at full load. Excessive temperature will not only melt various internal insulating materials, but even burn the The windings also melt away.
Therefore, in order to ensure that it does not overheat, many car companies strictly limit the speed of the motor, which leads to the inability of many trams to exert the ultimate acceleration, extreme speed and other performances; only when the heat dissipation is improved, the motor can release the limit and continue to develop possibility.
