Abstract
The production process are broken frequently due to the motor in operation are damaged, which is caused by abnormally running conditions. The intelligent motor protectors can be used, which will protect the abnormally running motors from damage, to minimize the malfunction time and reduce the economic losses. In this paper, a single-chip microcomputer, PIC16F877, based intelligent motor protector with functions of short-circuit protection,locked motor protection,phrase failure protection ,the overload protection ,over-voltage protection and under-voltage protection is designed on the basis of analyzing the development and status quo of motor protectors in the world.
In this thesis, the detailed analysis applied symmetrical component method of motor’s familiar electric fault on that a high-reliability implemental method of motor’s fault protection is provided according to the features of PIC16F877 microprocessor. The system is provided with A/D conversion interface used to sampling the input current of the motor and the structure is compact. Compared with the protection instrument for motor nowadays, this system increases functions such as dynamic LCD screen driven circuit to display different information.
According to the implemental method of motor’s fault protection the entire circuit diagrams are designed and the system software structure been easy to implement.
Keywords:Three-phrase motor protection; Single chip microcomputer; protection characteristic