对变频电源供电电动机的技术分析

作为变频器供电的电动机,由于变频器在换流过程中电动机释放电感贮能引起电压突变,叠加在运行电压上,而产生冲击电压,同时将使电动机上的电流波形呈现为一个叠加谐波的正弦波,该谐波电流将使异步电动机的磁路中产生一个脉动的磁通分量,此磁通分量叠加在主磁通上,使电机损耗增加,产生电磁振动和噪声,并产生对电机绝缘的冲击电压及轴电压,对电动机的对地绝缘形成威胁。对变频电源供电电动机产生的技术问题及解决办法做了详实的论述。

Entropy Generation Analysis in Convective Ferromagnetic Nano Blood Flow Through a Composite Stenosed Arteries with Permeable Wall

The study of heat transfer is of significant importance in many biological and biomedical industry problems.This investigation comprises of the study of entropy generation analysis of the blood flow in the arteries with permeable walls. The convection through the flow is studied with compliments to the entropy generation. Governing problem is formulized and solved for low Reynold's number and long wavelength approximations. Exact analytical solutions have been obtained and are analyzed graphically. It is seen that temperature for pure water is lower as compared to the copper water. It gains magnitude with an increase in the slip parameter.