The Relationship Between Motor Efficiency and Power Factor

As the two extremely important parameters of the motor, the motor efficiency and power factor are often the basis for selection. What is the relationship between the efficiency of the three-phase asynchronous motor and the power factor? Let's find out together.

There is a conflict between motor efficiency and power factors. The same electric motor, high efficiency, and the power is also because of the small number. On the contrary, the low efficiency is the power factor, and the high power is the motor; if the power factor is small, the transmission efficiency of the power grid will be reduced, because the power factor is small, so the power grid has no power consumption. Therefore, for the attack of the AC induction point, it is not only necessary to put forward higher requirements for the efficiency index, but also to put forward higher requirements for the power factor index.

Motor efficiency is low, indicating large losses. For an AC motor, the loss is resistive, so the larger the loss, the larger the P in the power triangle, the smaller the power factor angle φ, and the larger the power factor cosφ. On the contrary, the efficiency is high, indicating that the loss is small. In the power triangle, the P is also smaller, the power factor angle φ becomes smaller, and the power factor cosφ becomes smaller. In order to meet the two indicators of the power factor and efficiency of the motor, it is often necessary to pay attention to the other. If the power factor is to be improved, the clearance of the motor should be reduced and each connected ramp should be increased. To improve the efficiency, the motor clearance should be increased, which can reduce the dispersion loss of the harmonics, because the ratio of the dispersion loss of the harmonics to the spatial dispersion loss is 1.5 to 1.6. The measures taken by the two are exactly the opposite.