Life expectancy of electrical machines with variable loads
Life expectancy of electrical machines with variable loads
复制标题
可变负载电机的预期寿命
DOI：
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发表时间：
1960
期刊：
影响因子：
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通讯作者：
J. B. Uri
中科院分区：
文献类型：
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作者：
J. B. Uri
现代经济学要求降低成本和价格，这通常意味着减少材料的使用量。危险在于，使用中的一些绝缘材料具有纤维素基，这意味着如果温度高于110°C，则可能危及它们的老化，因为在该温度以上，纤维素材料倾向于迅速改变其稠度和机械强度。人们普遍认为，电机在额定负载下连续工作的预期寿命应为7年。Montsinger和Bussing已经通过实验和部分演绎找到并提出了预期寿命随温度变化的一般方程，实验表明这些方程对连续载荷是正确的。但当负荷变化时，必须考虑加热和冷却时间。短路或严重过载可能非常危险。已经开发了用于负载变化以及用于直线和指数温度变化的方程，并且表明冷却期尤其可能是非常危险的，并且占据所讨论的电气设备的预期寿命的非常可观的部分。包括对Transformer和间歇电动机负载的示例计算。
Modern economics demand a reduction in costs and prices, and this usually means reduction in the amount of materials used. The danger is that some of the insulation materials in use have a cellulose base, which means that their ageing may be endangered if the temperature is higher than the 110°C, since, above this temperature, the cellulose materials tend to change quickly their consistency and mechanical strength. It has been generally agreed that the life expectancy of electrical machines should be seven years when continuously under rated load. General equations for change in life expectancy with temperature have been experimentally and partly deductively found and presented by Montsinger and Bussing, and experiments show that the equations are correct for continuous loads. But when the load changes the heating and cooling periods must be taken into consideration. Short-circuits or heavy overloads can be very dangerous. Equations have been developed for load changes and for straight line and exponential temperature changes, and it is shown that the cooling-off period especially can be very dangerous and take a very appreciable part of the life expectancy of the electrical equipment in question. Sample calculations on transformer and intermittent motor loads are included.