For micro motors with the same torque, the higher the speed, the higher the efficiency. Slip is a parameter unique to micro motors. It can be found that the speed of a high-efficiency micro motor is higher than that of an ordinary micro motor, or the slip is smaller. The slip of a micro motor is closely related to the rotor winding resistance. A large resistance and a large slip result in a large rotor resistance loss, which leads to a low efficiency value and a small slip.
So, what are the fundamental reasons for the reduced efficiency of micro motors?
1. Micro motor stator copper loss is large
(1) High resistance of micro motor windings: such as high resistivity of wires, small wire diameter, uneven wire diameter, incorrect wiring, or weak welding, etc.
(2) Large stator current: such as large other losses, asymmetrical stator windings, uneven air gap between stator and rotor, fewer turns than normal, incorrect winding connection, etc.
2. Micro motor rotor copper loss is large.
(1) High resistance of micro motor rotor winding: copper has high resistivity, aluminum rotor end ring has air holes or impurities, materials do not meet requirements, rotor is incorrect, etc.
(2) Large rotor current: For example, if the alloy rotor uses ordinary aluminum or the rotor core is not tightly stacked, the rotor lateral current is too large.
3. Micro motors have high iron losses.
Poor quality or incorrect materials of silicon steel sheets for micro motors, poor insulation of stator cores, excessive core stacking pressure, short circuits in core sheets, etc.
4. High mechanical wear
Problems include bearing overheating and inflexible rotation, small bearing housing diameter, poor lubrication quality, rubbing during bearing operation, and high frictional resistance.
