Design And Investigation Of The Motor Protector With The Function Of Power Meter

Three-phase motor is one of broad-spectrum equipments in electrical and mechanical industry. Its driving force is the precondition that driven equipment can work normally. As a result, it is very needful to use a protector which can monitor malfunction of three-phase motor correctly and fleetly. It can get the energy consumption situation of three-phase motor by measuring its rate of work on-line. But, nowadays many protectors of three-phase motor have not the function of measure of power. After studying the theory and technique for three-phase motor protection and power measure, a scheme for protector and dynamometer of three-phase motor based on Xin Hualong C8051 F340 and ATT7022B.Based on the analyzing and studying of the theorem of three-phase motor and Support Vector Machine(SVM), a soft sensor model is built to estimate the temperature of three-phase motor by modeling with SVM. As a try of temperature indirectly measure of three-phase motor, it is an extension for soft sensors.In order to achieve the target, the hardware system is designed. It includes signal process circuit, main control circuit, power measure circuit, switching power supply circuit, keyboard and display circuit as well as communication circuit. Correspondingly, the software system is also designed. It includes initialization program, supervision and protect program module, dynamometer program module, keyboard and display program module as well as communication program module. The experiment and application proves that the scheme not only can monitor many kinds of malfunction of three-phase motor stably but also can display much information on-line, such as voltage, ampere and watt.The product is designed by unified formalism. It is not only a protector, but also a dynamometer for three-phase motor. Reduces the cost of the product, and avoids the waste of using equipments with single function and make it possible to simplify and miniaturization control cabinet. And, also it makes it easy to fix and maintenance three-phase motor. Therefore, the product has economic benefit and broad prospects in industrial production.