外文翻译--恒压供水变频器.doc

Constant pressure water supply frequency changer The transistor frequency changer not only overcame has formerly exchanged velocity modulation many shortcomings, moreover the velocity modulation performance might compare favorably with the direct current motor velocity modulation performance.The three-phase asynchronous motor has the service to be convenient, merit andso on price small advantage, power and rotational speed adapt breadth, its frequency conversion velocity modulation technology in the miniaturization, the low cost and the redundant reliable aspect holds the obvious superiority. To the end of the 80s, the alternating current machine frequency conversion velocity modulation technology rapidly develops into a mature technology, it will supply the alternating current machine the labor frequency alternating current supply to turn direct currentafter the diode rectification, again by component and so on IGBT or GTR module counter will turn the alternating current supply which the frequency might move,will drive the electrical machinery by this power source to move under the speedchange condition, and automatic suitable strain load condition. After it changed in the traditional industry the electrical machinery to start only can by the ratedpower, decide the rotational speed the sole movement way, thus achieved the energy conservation goal. The modern frequency conversion velocity modulation technology applies in the electric power water pump water supply system. Because the frequency conversion velocity modulation has the velocity modula-tion the physical characteristics well, efficiency high, velocity modulation scope-wide, precision high, adjusting character curve smooth, may continual realize, thesteady velocity modulation, the volume small, the maintenance simple is conven-ient, the automated level higher a series of prominent merits but time peoples favor. When it applies especially in the air blower, the water pump and so on the large capaci