First, the motor load rate is low. Due to the improper selection of the motor, excessive surplus or changes in the production process, the actual working load of the motor is far less than the rated load, and the motor that accounts for about 30% to 40% of the installed capacity runs under the rated load of 30% to 50%. Efficiency is too low.

Second, the power supply voltage is asymmetric or the voltage is too low. Due to the unbalance of the single-phase load of the three-phase four-wire low-voltage power supply system, the three-phase voltage of the motor is asymmetrical, and the motor generates negative sequence torque. Losses in the operation of large motors. In addition, the grid voltage is low for a long time, which makes the motor current in normal operation too large, so the loss increases. The greater the three-phase voltage asymmetry, the lower the voltage, the greater the loss.

The third is that the old and old (obsolete) motors are still in use. These motors use class E insulation, are bulky, have poor starting performance, and are inefficient. Although it has undergone years of renovation, it is still in use in many places.

Fourth, poor maintenance management. Some units do not maintain the motors and equipment as required, and allow them to run for a long time, which makes the loss continue to increase.

Therefore, in view of these energy consumption performance, it is worth studying which energy saving scheme to choose.

There are roughly seven types of energy-saving solutions for motors:

1. Select energy-saving motor

Compared with ordinary motors, the high-efficiency motor optimizes the overall design, selects high-quality copper windings and silicon steel sheets, reduces various losses, reduces losses by 20%~30%, and improves efficiency by 2%~7%; payback period Usually 1-2 years, some months. In comparison, the high-efficiency motor is 0.413% more efficient than the J02 series motor. Therefore, it is imperative to replace the old electric motors with high-efficiency electric motors.

2. Appropriate selection of motor capacity to achieve energy saving

The state has made the following regulations for the three operating areas of three-phase asynchronous motors: the economic operation area is between 70% and 100% of the load rate; the general operation area is between 40% and 70% of the load rate; the load rate is 40% The following are non-economic operating areas. Improper selection of motor capacity will undoubtedly result in waste of electric energy. Therefore, using a suitable motor to improve the power factor and load rate can reduce power loss and save energy.

3. Use magnetic slot wedge instead of original slot wedge

4. Adopt Y/△ automatic conversion device

In order to solve the waste of electric energy when the equipment is lightly loaded, on the premise of not replacing the motor, a Y/△ automatic conversion device can be used to achieve the purpose of saving electricity. Because in the three-phase AC power grid, the voltage obtained by the different connection of the load is different, so the energy absorbed from the power grid is also different.

5. Motor power factor reactive power compensation

Improving power factor and reducing power loss are the main purposes of reactive power compensation. The power factor is equal to the ratio of active power to apparent power. Usually, a low power factor will cause excessive current. For a given load, when the supply voltage is constant, the lower the power factor, the greater the current. Therefore, the power factor is as high as possible to save electric energy.

6. Frequency conversion speed regulation

7. Liquid speed regulation of winding motor

Jessica