Comparison of common electric motors for electric vehicles:
How to identify the quality of the motor? What are the key parameters?
A: Mainly the magnitude of no-load current and riding current, compared with normal values, and the efficiency and torque of the motor, as well as the noise, vibration and heat of the motor, the best way is to test the efficiency curve with a dynamometer.
★What is the difference between 180W and 250W motors? What are the requirements for the controller?
Answer: The riding current of 250W is large, which requires high power margin and reliability of the controller.
★Why in a standard environment, the riding current of an electric car will vary depending on the rating of the motor?
A: It is well known that under standard conditions, the rated current is 160W. The riding current on a 250W DC motor is about 4-5A, while the riding current on a 350W DC motor is slightly higher. For example, if the battery voltage is 48V, the two motors 250W and 350W, the rated efficiency point is 80%, the rated operating current of the 250W motor is about 6.5A, and the rated working current of the 350W motor is about 9A. The efficiency point of the general motor is that the farther the operating current deviates from the rated working current, the smaller the value is. Under the load condition of 4-5A, the motor efficiency at 250W is 70%, and the motor efficiency of 350W is 60%. Under the load of 5A, the output power of 250W is 48V*5A*70%=168W, and the output power of 350W is 48V*5A*60%=144W.
In order to make the output power meet the riding requirement of 168W (almost the rated load), the 350W motor only increases the power supply, thus increasing the efficiency point.
★Why in the same environment, the 350W motor is shorter than the 250W motor electric vehicle?
A: Due to the same environment, the 350W motor's electric vehicle has a large riding current, so in the case of the same battery, its mileage will be short.
