丹佛斯变频器VLT2000系列英文说明书pdf,Afrequencyconverterisanelectronicunitforinfinite speedcontrolofa.c.motors.Thefrequencyconverter controlsthemotor speed byconvertingthefixedvoltage andfrequencyofthesupplymains,e.g.400V/50Hz,tovariablevalues.