Design Of Multi-functional Protector Of Motor Based On Modbus And ARM7

At present domestic market, the function of motor protector is unitary relatively and the protection algorithm isn't perfect .The data processing speed and performance of some hardware chips of the protector are not high. The man-machine interface is unfriendly. The motor often couldn't get timely and effective protection, which lead to grave accidents and significant economic losses .Relative mature product has been offered by some foreign manufactures and scientific research institutions, but the price is very high. The research is proposed based on such background.This issue optimized the algorithm of protection and presents a protection scheme of motor for multiple faults firstly, which make up the shortage of traditional motor protector. The improved method of phase-sensitive protection is used to protect electric motor with symmetrical breakdown. Symmetrical component method is used to realize asymmetric fault protection. Inverse-time characteristics method and the heat accumulation model are combined to realize overload protection. The method of additional direct-current power is used to realize leakage protection.Based on the analysis of protection principle, this issue designed a kind of motor protector which can realize many functions such as fault diagnosis, fault protection, fault alarm, fault record, after the failure analysis, fault location, liquid crystal display, communications. The protector is operated easily and debugged conveniently. Compared to the protectors that have emerged in the market, this motor protector has highlighted advantages. The advanced embedded technology is used to improve the data processing speed and performance of the protector and reduce costs. LPC2119 which is ARM7 chip is used to be the hardcore of the protector. The embedded real time operation systemμC/OS_II is transplanted to LPC2119, which can improve the real-time performance of the protector . The technology of Modbus is used in this issue, which is widely supported by the automatic equipment in the underground mine because of its simple protocol and the low cost. The protector is attached to the fieldbus, which realize the communication with other equipment and the monitoring system. The operator not only can control the protector nearly, but also can monitor the motor online and control remotely. Outside of that, the design provide the possibility of the constantly improvement of the protection program by the powerful resource of the computer network.The performance tests of protection and communication of the motor protector are introduced in this issue. The result indicates that the protector which has high anti-interference ability and acts sensitively and reliably has reached the design specifications and requirements.