Speed Adjustable Rotary Lobe PumpsMotor ＋ Stepless Speed ReducerThe main character of this type of reducer is that the speed can be adjusted manually. The speed range is usually 200-500rpm or 40-400rpm according do different applications.The speed can be adjusted smoothly within its range.The adjustment can only be undertook when motor is working. This reducer is not suggested where overload or blockage is easy occurring.