Large Motor Microprocessor-based Protection And Control Devices

This paper is about a kind of micro-controller controlled intellectual protection and control device for middle and large sized motor. I have researched one of the key technologies for the protection and control device: the real-time sampling technology for the valid value of the quantity of alternating current. I have also studied the method of rri-sampling, Fu's algorithm of full cycle and the algorithm of root-mean-square. It will meet the requirements of not only anti-disturbance but also quantity testing if the algorithm of root-mean-square is adopted and the expected effect is reached when I adopted this method in the designed device. On the other hand, this paper also expatiates familiar failures of motor and 1 also researched motor protection principles and the characters.I have designed a device with the master chip of 80C196KC single chip micro-controller and the main design includes system hardware and software. The device has realized the real-time control and protection for short circuit, failure to start, unbalance (open phase), under-voltage, earth faults, and overload.The device has considered its practical functions, which include Chinese character parameter, waveform display for three-phase current, fixed value and retain of failure information.I have also designed experimental analog circuit to check the performance of the device, which is tested to meet the index and requirement of this design.