Performance of the motor efficiency is very important, especially in energy conservation and emissions reduction policy guidance, of the efficiency of motor users have special attention. If you want to accurately measure the efficiency of the motor, the need to conduct pilot test, and through the appropriate test method, standard of efficiency. Method to determine the efficiency of three-phase asynchronous motor as an example, the general can be divided into three categories. The first is direct measurement; The second category is the indirect measuring method, also known as loss analysis; After the third class is through simple test reuse method of theoretical calculation, a simple call it a theoretical calculation method.
direct measurement method is intuitive, simple, and the relative accuracy is higher, but not conducive to a concrete analysis of the performance of motor and a targeted improvement; Indirect measurement test project is more, laborious, and more, the amount of calculation, is a comprehensive accuracy than direct measurement, but it can show the motor efficiency is the main component of the specific circumstances, so as to facilitate the motor design, manufacturing process and the problems in a targeted analysis, and by improving the motor performance requirements or further improve; The theoretical calculation method is used on testing equipment, the accuracy of the worst.
A method & ndash; —The efficiency of the direct test method
- are commonly known as A method of inputOutput method, due to the test when two data of calculating efficiency can be obtained directly, namely, the input power and output power.
in subjects motor load, run to the stable temperature or after the specified time (When the latter method is adopted, the participants with the motor winding temperature and actual temperature stability of the temperature difference should be no more than 5 k)In 1, adjust the load. 5 to 0. 25 times rated power range change, the acquisition work load down and up the two characteristic curve. Each curve acquisition of not less than 6 readings, each point of reading include: three phase line voltage (Should maintain a rating), three phase line current, input power, speed, torque, conditional should also record the output power. Finally power outage, within the prescribed time inside of the stator winding dc resistance, otherwise should be according to the relevant provisions of the heat after test to calculate the thermal resistance of extrapolation is modified.
when conditional priority (measurement by chargedSuperposition method)Or in advance in the winding embedded thermocouple or copper (Platinum)Thermal resistance temperature sensor for each point of the stator winding temperature or resistance method. Should also record the environment temperature test. brushless motor manufacturers
