The highest mechanical variable loss of a cheap motor mech is: the loss of the DC generator mainly includes: (1) copper loss of the field winding; (2) mechanical friction loss; (3) iron loss; (4) armature copper loss; (5) ) Brush loss; (6) Additional loss.
Iron loss refers to the hysteresis and eddy current loss in the silicon steel sheet when the armature core rotates in a magnetic field. These two losses are related to the magnetic density and the alternating frequency. When the excitation current and speed of the motor are unchanged, the iron loss is almost unchanged. It has almost nothing to do with changes in load. The armature copper loss is caused by the armature current. When the load increases, the armature current increases at the same time, and the armature copper loss increases accordingly. The armature copper loss is proportional to the square of the armature current. The efficiency is the highest when the load factor is 50%. At this time, the load loss of the transformer = no-load loss. Therefore, when constant loss=variable loss, the efficiency of the transformer is the highest. The variable loss is the copper loss on the armature winding and the power consumed by the excitation circuit of the shunt motor. The constant loss is the friction loss of the motor and the hysteresis loss and eddy current loss in the armature, that is, the iron loss.
