理论上，电机效率受电机负载和频率的影响。电机等效电路法为估计电机效率提供了一种有效的方法。然而，电路参数通常必须通过现场测试来确定，这在系统运行时是不可能进行的。基于在额定频率下四种负载水平下测量的电机效率和功率因数数据总是被公布的事实，提出了一种利用公布的数据识别电路参数的迭代方法。电路参数用于估计不同频率下的电机效率。本文首先对电机效率与功率因数数据及电路参数之间的数学关系进行了公式化，然后给出了最小值- 在额定频率下，利用已公布的数据，利用平方法识别电路参数，最后估计不同频率下的电机效率。引文:美国科学与技术研究院学报第119卷第2部分，科罗拉多州丹佛市。

Theoretically, motor efficiency is impacted by motor loadas well as frequency. The motor equivalent circuit methodprovides an effective method to estimate motor efficiency.However, the circuit parameters normally have to be determinedthrough field tests, which are impossible to conductwhen systems are in service. Based on the fact that measuredmotor efficiency and power factor data at four load levelsunder the rated frequency are always published, an iterativemethod is proposed to identify the circuit parameters usingpublished data. The circuit parameters are used to estimate themotor efficiency under different frequencies. In this paper, themathematical relations between motor efficiency and powerfactordata and the circuit parameters are first formularized,then the least-squares method is utilized to identify the circuitparameters using the published data under the ratedfrequency, and finally the motor efficiency is estimated underdifferent frequencies.