The motor in use on the market is generally brushless low speed, brushless high speed, brushless low speed and other brushless high speed is not commonly used.
The main difference between high speed and low speed is whether the gear reducer reduces the speed of the motor in order to improve the efficiency of the motor at low speed and increase the output torque of the motor at low speed. In general, high speed motors are equipped with clutches to make the outer hub disengage from the motor load when the motor is not in power and to lengthen the sliding distance. The structure of high-speed motor is complex, the cost is low, the speed is high, and the efficiency decreases with the increase of gear wear noise.
In judging the performance of the motor, we mainly have the following indicators:
1 motor noise. Noise Every motor has but no metal collision, pinball extrusion, friction noise allows uniform electromagnetic noise which can be monitored by hollow metal listening rod on the motor shaft.
No-load current of motor. Detecting the no-load current of the motor mainly reflects the wear loss of the demagnetizing machine of the motor. If the current increases and the no-load speed of the motor increases, the demagnetization phenomenon is more obvious.
Load current of motor. Detecting the load current of the motor mainly reflects the actual operation efficiency of the motor. If the load current increases but the actual torque is small, it is necessary to check the magnetic energy product of the magnet and the soldering inside the coil. It is also important to check whether the commutator has short circuit for the brush motor. In the on-line detection of Hall switch type of brushless motor, the main test is whether the change of Hall signal is correct or not. Generally, the change times of high and low voltage alternating current are half of the number of magnets.
If we look carefully at the variation of the voltage of each line, we can find that it is a regular six repetition cycles. For 120 degree motor, the variation should be 100, 110, 010, 011, 001, 101 and for 60 degree motor, the variation should be 100, 110, 111, 011, 001, 000. In addition, when repairing Hall of brushless motor, attention should be paid to the type of Hall. When welding, anti-static gloves or wrist branding iron must be worn. It is better to weld off-line and pay attention to the positive and negative sides of Hall. When repairing the brush motor with carbon brush, first put the carbon brush in the brush grip to tighten the soft copper lead wire of the carbon brush and fix it in the lead slot until the inner stator is fully put into the external transmitter, then relax the carbon brush and check the flexibility of the carbon brush.