... negative feedback, the rate of change of speed are less than 2.5%.2.Structure are simple, use and maintenance conveniently, cheap.3 ... .Operating environment:1.Air temperature no more than 40 ℃, altitude less than 1000m2.Relative humidity NO MORE THAN 90%Make sure ... less dust, and working in without explosive tendency medium, that must be corrosion metal and damaging insulating air , and ...