The Technology Of Measuring And Controlling In The Test Of Electrical Apparatus

Nowadays, electrical apparatus manufacturers have designed many measuring and controlling equipments, which are used to test whether their electrical apparatus products have reached national or international standard. But we have found some problems from those equipments.In the first place, the adjusting methods of boosters need optimizing. In the test of electrical apparatus, we often adjust boosters to get exact voltage with hands. A disadvantage of this method is that the voltage is not very precise, and it also hasn't the steady performance. So I add computer technology into my work. The testing voltage becomes more exact than before using digital adjustment. On the other hand, I combine fuzzy-control method with self-adapting control method together, and design a fuzzy self-adapting control method. I employ computer to get steady voltage. I contrast this method with PID control method, and then I see that as far as the step response is concerned, my approach is not much advantageous than PID control method. But when the gain of controlled object changed greatly, my approach is improved considerably.In the second place, the computer measuring methods of electrical parameters need improved in the test of electrical apparatus. When the contacts are connected into direct circuit, we can judge whether the contacts are open or not through analyzing the voltage instantaneous values across the two contacts. Whereas if the contacts are in series with the alternating circuit, due to the passing zero property of voltage, we must evaluate the condition of contacts according to voltage value. The traditional method is that sampling 20 equidistance discrete voltages to calculate the virtual value. To gain the virtual value, we firstly average their square values, and then extract it. The defect of this method is that the virtual value will lag the instantaneous value about one cycle. This event result in the virtual value is not exact. We design a fast calculating amplitude method: obtain two instantaneous voltages at first, after that calculate the current voltage virtual value once we get another instantaneous voltage. This method can be used to control booster, and also can be used to measure all time parameters.The two problems have been solved and been used in actual project. They have the merits of running stably and smoothly.