This article mainly analyzes the motor in the use of energy loss in the process of composition, mainly introduced how to reduce the mechanical loss of the motor running, reach the purpose of energy saving and efficiency increasing.

1. The composition of asynchronous motor energy loss

(1) : copper loss of the stator copper loss; The rotor copper loss; Stray loss.

(2) the core loss.

(3) : mechanical consumption ventilation loss; The friction loss.

From the above list of asynchronous motor energy loss, copper loss and iron loss in our repair is not easy to change, they are decided by the design, the mechanical loss can be changed. Asynchronous motor is generally less series of revolutions namely high mechanical loss is bigger, the motor copper loss is less; And series more namely low RPM the motor copper loss percentage accounted for the mechanical loss is big. So, we want to reduce the energy loss of the motor will solve from the reduce the mechanical loss of the motor.

2. Reduce the loss of the motor mechanical main method

Reduce motor mechanical consumption is mainly from the following several aspects:

(1) USES efficient fan (such as wing type axial flow fan).

(2) to adjust the wind shield and the clearance between the cylindrical blades.

(3) appropriate to reduce the light load motor fan diameter.

(4) using high quality bearings.

(5) high quality lubricant.

(6) improve the quality of the motor assembly.

3. The specific measures to reduce the loss of the motor mechanical

First of all, let's look at how to energy saving, by changing the fan size is known to all motor are the devices that convert electrical energy into mechanical energy, in the process of transformation to produce loss, the loss in the form of heat, it makes the motor fever. Custom windings are produced after electric current flows through the copper loss, give the stator iron core, the heat conduction through the slot insulation materials by stator core to the motor shell again send out into space. Rotor heat is generated by the rotor aluminum consumption and its friction, it passed to the rotor iron core and inner surface of the fan, with the fan mixing space, make the heat dissipation in motor in to the stator core, end cover, frame, fixed, rotor both strands of heat from outside the fan blows away. Outside the fan air volume, therefore, is to determine the size of the motor temperature cannot exceed their level of insulation material is allowed to temperature is the key.

Standard regulations of the state to deal with all kinds of insulation class allows the temperature rise of motors under rated operating conditions, the most hot spot temperature requirements motor does not allow more than the limit temperature of the insulation class, and the motor insulation class is commonly used in the following table: : allow temperature = allow e. - winding hot spot temperature difference temperature limit - the environment temperature of hot spot temperature difference make refers to when the motor with rated load, the stability of the winding hot spot temperature with the average temperature of winding.

When the motor is in no load or light load, motor to total loss assessments timing is small, and the air volume is proportional to the total loss of motor, so the fan in the "big horse-drawn cart" (because of the loss and the motor speed constant ventilation, the ventilation loss does not change with load, so at this time should reduce airflow to reduce the ventilation loss) of the motor. Change the fan blade shape can reduce the air volume, but more troublesome, as direct reduce fan blade diameter to reduce the air volume to be more simple. We know that the fan itself mechanical loss according to the 4, 5 times the diameter of the blade is proportional to the air volume with the blades is proportional to the square of the diameter, so reduce the blade diameter, volume reduced, and the ventilation loss is reduced a lot.

Due to external fan cooling air volume to reduce motor temperature rise, but still keep the motor temperature rise within the scope of the insulation class allows. At the same time, we also need to see because of outside diameter blades to reduce the motor mechanical consumption is reduced, and can make the motor temperature rise further reduced. Especially for high speed motor grade 2, 4, when the fan is 14% - 14% smaller diameter, ventilation loss reduce 20% - 20%. In addition, changing the diameter of the blade at the same time, to the corresponding change wind deflector or fan casing size, making them cooperate with each other size is in line with regulations. Fan blade and fan cover the gap is too large, typically between 10-15, after the air leakage loss of back into the conference board high to a low pressure area, at the same time to keep the Angle between the fan and fan cover, its role is to make the part of the inlet air dynamic pressure into a static pressure and reduce the loss. Such as base 8 with the fan can be adjusted and repair using 9 stand light load on the motor, so that it can make the 9 stand the light load motor to reduce the mechanical consumption, and makes the temperature rise to improve to improve the efficiency and power factor of the motor.

3.1 reduce friction in order to reduce mechanical wear and tear

The normal operation of motor bearings, noise, vibration, overheating, life and other factors related to choose the grease, but usually USES 3 for the lithium base grease, can reduce the mechanical consumption, but the current with the rapid development of science and technology and many superior performance of grease, such as: "small and medium-sized motor bearing grease" its performance by the relevant department test reached the standard of Japanese JIS2220-80 rolling bearing grease, close to the Swiss SKF65C grease level, with impurity is extremely low, price and the no. 3, lithium base grease. In the current appear on the market of the United States ai rope grease performance is good too. We can use these performance good grease to improve the performance of the motor to reduce mechanical wear and tear. As motor professional maintenance staff we can choose in reasonable bearing fluctuation kongfu, also can saving energy and reducing consumption; Since we already know that the number of less motor mechanical loss is big, series of motor mechanical consumption is small. We can use in the repair of motor selection of the bearing. On high speed motor, for example, we can use the import bearings or domestic senior grade B, C quality bearing chamber to minimize loss. And we can use in low speed motor home-made C, D, so that we can save on bearing, so as to achieve saving energy and reducing consumption of female.

3.2 improve the power factor in order to reduce mechanical wear and tear

A turnaround in the drag power factory equipment 95% is ac asynchronous motor, and ac asynchronous motor is a low power factor of the equipment. If improve the power factor of the problem we discussed.

3.2.1 reasonably adjust operation equipment, and improve the power factor

Before make artificial compensation, consideration should be given to existing power plant equipment inspection and adjustment, make its reasonable operation, so as to improve the power factor.

(1) in general power plant equipment is complete without consideration on capacity and type selection, we only need to consider motor in operation, and avoid the "big horse-drawn cart" phenomenon, when load rate lower than 40%, can consider to change the small capacity of the motor. When the load rate lower than 30%, the delta winding can be changed to y connection and operation mode, so that the efficiency of the motor and power factor are increased.

(2) the old series motor, such as: J0, J02 series of old motor is modified or eliminated, replace the Y series of energy-saving motor.

(3) the proper use and maintenance of motor, pay attention to the control of its frequent start (low frequent startup power factor), elaborate maintenance, adjust the centerline and motor when the motor is installed, static son clearance is indispensable, because of the uneven air gap will cause the no-load current increase, lower power factor.

3.2.2 equipped with frequency converter, and improve the power factor

Using frequency converter speed control to achieve the purpose of raising power factor, also is commonly used energy-saving method, namely the general ac asynchronous motor with frequency converter, the method simple installation, convenient operation, energy saving effect.