According to the analysis of the current of the motor, it is necessary to analyze and compare the actual running current of the ordinary motor and the high-efficiency motor.

1.1 No-load current The no-load current of the motor is mainly determined by the density of the magnetic flux and the length of the air gap between the stator and rotor. Will become less. Under normal circumstances, the air gap length of the motor is relatively small, usually a few millimeters. For this reason, the main magnetic flux will pass through the loop, and the length of the air gap will be small at this time, which is one percent of the length of the entire magnetic loop. Because the permeance of the silicon steel sheet is greater than that in the air, for this reason, for the no-load current of the motor, the density of the magnetic flux affects the length of the air gap.

1.1.1 In terms of magnetic flux density, high-efficiency motors need to increase the length of the iron core. At this time, the magnetic permeability performance needs to choose cold-rolled silicon steel sheets. Compared with the load current, the no-load current of the high-efficiency motor will become smaller.

1.1.2 The air gap length is aimed at the specifications of the motor’s low power. Due to the stray loss, the actual efficiency of the motor will be seriously affected. For this reason, the length of the air gap needs to be controlled during the design process of the high-efficiency motor. The parameters are caused by the air gap. Therefore, when comparing low-power motors, the actual effect of the air gap length on the no-load current can be ignored. For high-power motors, the efficiency of the motor will be affected by the additional loss at this time. Therefore, in the process of designing high-efficiency motors, the length of the air gap needs to be larger than the ordinary choice. For high-power motors, the air gap length of high-efficiency motors increases. Compared with ordinary motors, the no-load current of high-efficiency motors will increase, and the power will be very low.

1.1.3 Comprehensive analysis For low-power motors, it is usually because the length of the air gap is not enough, so that the density of the magnetic flux is reduced. For this reason, compared with the no-load current of ordinary motors, the actual no-load current of high-efficiency motors will be Very small. For high-power motors, although the magnetic flux density of high-efficiency motors has changed significantly, the air gap length of high-efficiency motors will become larger, resulting in the density of magnetic flux that will affect the air gap length. The no-load current of the motor will increase.

1.2 The calculation formula of the output shaft power of the load current motor: according to the different working conditions, such as voltage, temperature and output power, in the actual running motor, the voltage and the output shaft power belong to a constant, so K It is also constant. Under the same working conditions, the current of a high-power motor is compared with an ordinary motor. The operating current of a high-efficiency motor is determined by the difference between the excitation current of the motor and the efficiency of the motor. For high-power motors, the efficiency difference with ordinary motors is analyzed and compared. The value of high-efficiency motors is very small, so under the same working conditions, compared with ordinary motor current values, the active current of high-efficiency motors is very small, but there is no change. For this reason, in the actual operation of a high-efficiency motor, the current change is determined by the change of the exciting current, but it is only the running current.

By Jessica