Design Of Intelligent Motor Protector

As a kind of driving machine, motor is used in almost every professions and trades. It’s animportant guarantee of industry, agriculture, building up of national defense and people’snormal life. So the normal operation of the motor is very important. The motor protector is akind of the protective device of the motor. It plays a vital role in the motor’s safe operation.With the development of the modern electronic technology, the intelligent motor protectorcomes into being. For its high sensitivity, low price, strong operability and convenientmaintenance, it has a wide application prospect in today’s industrial areas. Therefore theresearch on intelligent motor protector has become an important project.In this paper, the theoretical analysis on the fault operations of the three-phaseasynchronous motor is carried out. The fault operations include overload, loss of phase, lockedrotor, ground fault, and so on. The current or voltage characteristics of the faults of motor areacquired. The protection principles of the intelligent motor protector for a variety of failures aredetermined. According to the protection principles, with PIC microcontroller as the core, thehardware system is designed, which includes the keyboard input circuit, the signal acquisitioncircuit, the display circuit, the output control circuit, and so on. And the software systemprogram is finished to realize the functions such as real time monitor, fault diagnosis anddisplay of the motor status. At the same time, by use of Max485module, the communicationdesign between the host computer and the intelligent motor protectors is completed to realizethe two-way communication. In addition, the anti-interference design of the intelligent motorprotector in hardware system and software system is studied on.