Abstract:The energy relationship of motor was derived to measure the the efficiency of the pump motor. The results show that the motor efficiency is related to the input power and running current of the motor. The calculation formula of motor operating efficiency was obtained. The standard test data of six different types of three-phase asynchronous motor were used to conduct a theoretical verification. The input power and running current of the motor were adopted in the calculation of operating efficiency, and compared with the the actual efficiency of the motor. The results show that the overall error between the calculation efficiency and the actual operating efficiency of the motor is less than 1.8%. To further prove the reliability of the scheme, the centrifugal pump test bench was designed to verify the test. The motor end load was controlled by adjusting the pump valve opening degree to obtain the motor calculation efficiency under different working conditions. The test results show that the error between calculation efficiency and the test efficiency value is less than 1.06%. Compared with the general test method, the program can calculate the operating efficiency quickly and accurately by reading its input power and current while the motor is running, without measuring other data or stopping the measurement, which greatly improves measurement efficiency.
[1]MENG F, ZHANG H, YANG F, et al. Study of efficiency of a multistage centrifugal pump used in engine waste heat recovery application[J]. Applied thermal engineering, 2017, 110: 779-786.[2]KUMAR S, GANDHI B K, MOHAPATRA S K. Performance characteristics of centrifugal slurry pump with multi-sized particulate bottom and fly ash mixtures[J]. Particulate science & technology, 2014, 32(5): 466-476.[3]WANG Y, LIU H, LIU D, et al. Application of the two-phase three-component computational model to predict cavitating flow in a centrifugal pump and its validation[J]. Computers & fluids, 2016, 131: 142-150.[4]张佩芳, 袁寿其, 许建强. 低比转速离心泵研究现状与发展前景[J]. 排灌机械, 2003, 21(6): 42-45. ZHANG Peifang, YUAN Shouqi, XU Jianqiang. Re-search status and development prospect of low specific speed centrifugal pump[J].Drainage and irrigation mechinery, 2003, 21(6): 42-45.(in Chinese)[5]周崇兴, 杨津听, 宋露,等. 三相异步电机损耗及运行效率的在线测量[J]. 变频器世界, 2014(3): 39-42. ZHOU Chongxing, YANG Jinting, SONG Lu, et al. On line measurement of loss and efficiency of three phase induction motors[J]. Inverter world, 2014(3): 39-42.(in Chinese)[6]李军丽. 三相笼型异步电动机负载杂散损耗的测试方法[J]. 电机与控制应用, 2009, 36(4): 44-48. LI Junli. Test method for load loss of three-phase squirrel cage induction motor[J]. Motor and control applications, 2009, 36(4): 44-48.(in Chinese)[7]王士增. 三相异步电动机运行效率的分析[J]. 电力标准化与计量, 1996(2): 1-2 WANG Shizeng. Analysis of operating efficiency of three phase asynchronous motor[J]. Electric power standardization and metrology, 1996(2): 1-2.(in Chinese)[8]曾国荣. 电机效率,轴功率和负载率的计量测试[J]. 冶金丛刊, 1997(4): 25-27. ZENG Guorong. The motor efficiency, shaft power and load rate measurement[J]. Metallurgical collections, 1997(4): 25-27.(in Chinese)[9]李阳, 张曾科, 常进. 基于转差率的感应电机最优效率控制[J]. 电机与控制学报, 2005, 9(3): 215-217. LI Yang, ZHANG Zengke, CHANG Jin. Optimal efficiency control of induction motors based on slip ratio[J]. Proceedings of the Chinese society of electrical engineering and control, 2005, 9(3): 215-217.(in Chinese)[10]方正. 三相异步电动机运行功率估算方法[J]. 电机技术, 2011(4): 43-45. FANG Zheng. Three phase asynchronous motor power estimation method[J]. Electric machine technology, 2011(4): 43-45.(in Chinese)[11]白连平, 徐广娇, 郑首印. 异步电动机负载率和运行效率的现场测试分析[J]. 电机技术, 2015(1): 29-32. BAI Lianping, XU Guangjiao, ZHENG Shouyin. Field test rate and efficiency analysis of asynchronous motor[J]. Motor technology, 2015(1): 29-32.(in Chinese)[12]杨斌文, 周志刚. 电机负载率的测定与正确运用[J]. 机电产品开发与创新, 2003(6): 24-25. YANG Binwen, ZHOU Zhigang. Determination and correct application of motor load ratio[J]. Mechanical and electrical products development and innovation, 2003(6): 24-25.(in Chinese)[13]秦和. 电动机效率测定方法的进展[J]. 中小型电机, 2004, 31(1): 65-74. QIN He. Development of measuring methods for motor efficiency[J]. Medium and small electrical machines, 2004, 31(1): 65-74.(in Chinese)[14]刘庆, 闫利丽. 电动机效率试验方法对比研究[J]. 防爆电机, 2011, 46(4): 38-40. LIU Qing, YAN Lili. Comparative study of motor efficiency test methods[J]. Explosion-proof motor, 2011, 46(4): 38-40.(in Chinese)