Abstract
Three-phase induction electrical motors are equipments with a simple structure, low cost, ease of maintenance and operation to meet the mechanical characteristics of the characteristics of the majority of the requirements of machinery, industrial control and electrical drive train system in a wide variety of applications. Therefore, their protection and control of research is essential.
When the asymmetric failures of electrical motors happen under symmetrical weight law, the current will show up positive sequence, negative and zero sequence currents. We identify the type of failure and use the sequence as the basement of illness protection
To ensure that the protection character of motors is the trend of the theory of motor development based on the sequence detection fault current weight and the use of the preface current weight and different combinations and use of size and worth a correlation between the type of failure .
Through the analysis of three-phase induction motors integrated protection principles, soft-start operation and control principles and the realization, we use a high-performance 80C196 as the computer central processing units. The combination of integrated protection, soft-start control and operational control
Makes protection and control integrated. This not only can supply
reliable protection but also can enforce soft-start and control the motor using less power. So we can make the protection of three-phase induction motors multiply digital and intelligent .
Key words: comprehensive protection;soft-start;power-saving;control