powerful electric gear reductions

gear reductions , also known as adjustable speed drives, are large industrial electric motors whose speed can be adjusted by means of an external controller. They are used in process control and help saving energy in plants that use many powerful electric motors. The use of adjustable speed in process control matches the gearbox motor speed to the required tasks and may compensate for changes in the process's variables. The use of adjustable speed for saving energy is exemplified by the adjusting the speed of a colling fan motor to match the temperature of the machinery parts it is cooling.