The motors in use on the market are generally brushed low speed, brushless high speed, and brushless low speed and so on. Brushless high speed is not commonly used.
The difference between high speed and low speed mainly depends on whether or not gear decelerates. The purpose of gear reduction is to improve the speed of 250 watt electric bike motor, so as to improve the efficiency of motor at low speed and increase the output torque at low speed.
Generally high speed motors are equipped with clutches, the purpose is to remove the load of the outer wheel when the motor does not work, so that the distance of the glide is lengthened, but the structure of the high speed motor is complicated and the cost is higher than that of the low speed motor. And with gear wear, noise increases, efficiency is reduced accordingly.
In judging the performance of the motor, we have the following main indicators:
There is noise in every motor, but there can be no metal equal collision, projectile extrusion, friction noise, allowing for uniform electromagnetic noise, these noises can be monitored on the motor shaft through hollow metal listening rods.
The detection of the no-load current of the motor mainly reflects the demagnetization of the motor and the wear loss of the machinery. If the current increases, the speed of the motor without load increases, which shows that the phenomenon of demagnetization is obvious in general.