Research On Intelligent Asynchronous Motor Speed Measuring System

The intelligent asynchronous motor speed measuring system researched by this subjectis based on STC12C5630MCU, using an inductor for the sensor. It gets electrical signalsrelated to the motor speed in the triphase asynchronous motor leakage field, and handlesthem to calculate the motor speed. This system can be differently configured according tothe environment where the motor is. On current research process, it is assorted to two types:instrument and transducer. The former with abundant human machine interface is equal toan intelligent motor speed measuring instrument, users can read the real-time motor speedby the LCD. This project is mainly used for the motors that are placed in the atmosphere.The latter without the human machine interface integrates the sensor with the handle circuit.It converts the speed data to the standard4-20mA.DC analog current signal. This projectis intended to meet the submersible motors’ measuring requirement, and assures the speeddata signals to transfer safely in industrial environment.The article firstly introduces the usual triphase asynchronous motor speed measuringmethods in modern industry, and expounds the necessity and feasibility of studying theintelligent asynchronous motor speed measuring system. It then discusses the system’stheoretical basis, and following tells the software and hardware design to achieve thesystem’s function in detail. It lastly analyzes the system’s stability, data’s accuracy andprecision by measuring experiments. The hardware design contains the sensor part andcircuit part, that is the design of inductor, signal conditioning circuit module, MCU handlemodule,4-20mA.DC conversion module, RS485communication module and system’spower supply module. The software design adopts the period measuring method to get thesignals’ frequency, and uses the median filter and the linear interpolation methods toenhance the system’s precision.The system has an upper measuring precision. It can measure the common triphaseasynchronous motor speed. It can be also used for the measuring of the hiding reelasynchronous motor speed, and makes up for the shortage of using other methods. Thestudy of this system has not only practical significance for enterprise projects, but also theimportant meanings for the commercial run and detection of the triphase asynchronousmotor.