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Switching electrical appliances used air or transformer oil as arc extinguishing medium in the early 20th century. After multi-oil, oil-less, compressed air type, they developed into circuit breakers that use vacuum as arc extinguishing medium and sulfur hexafluoride as arc extinguishing medium. Its breaking capacity is from about 20 to 30 kiloamperes in the early period to 80 to 100 kiloamperes in the mid and late 1980s, and the working voltage is increased to 765 kilovolts to 1150 kilovolts. For example, in the 1960s, transistor time relays, proximity switches, and thyristor switches appeared. After the 1970s, there were electromechanical integrated intelligent appliances and sulfur hexafluoride fully enclosed combined electrical appliances.
The emergence of these electrical appliances is interdependent and mutually reinforcing with new electrical materials, new electrical manufacturing technologies and new processes, and has adapted to the requirements of the continuous development of the entire power industry and social electrification. The transparency of the high-end image prices and the diminishing profits of electric appliance companies are becoming more and more obvious in the middle and low-end small household electrical appliances. More electrical appliances companies will seek low-end and high-end profits. How to further quantify the benefits is the realm that many companies pursue. At the same time, the transformation of consumer attitudes has also contributed to the development of high-end electrical products.
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