{"content":[{"text":"E-Notes \n Energy Efficiency Notes","bbox":{"left":0.117647,"top":0.083809,"width":0.312137,"height":0.103331}},{"text":"Energy Efficient Electric Motors and Drive Systems","bbox":{"left":0.117647,"top":0.261006,"width":0.6631719999999999,"height":0.03284500000000001}},{"text":"Background \n Conventional electric motors are large users of energy. It is estimated that 62% of all the electricity in \n the United States is used to drive electric motors. In many industries, about 70% of all the electricity \n used is for electric motors. \n Increasing the efficiency of drivepower systems can save large amounts of energy and money. \n Motors are parts of drivepower systems. For optimum performance, all parts of the drivepower \n systems must be carefully designed. \n In a typical belt-driven fan application in a building, the following drivepower system exists.","bbox":{"left":0.117647,"top":0.310886,"width":0.7384790000000001,"height":0.152652}},{"text":"Transformer--circuit breaker--electric wiring--motor panel--power factor correction equipment-- \n electric wiring--electric motor--fan belts--fan wheel and casing--duct system.","bbox":{"left":0.117647,"top":0.481205,"width":0.7160880000000001,"height":0.03915100000000005}},{"text":"The electric motor is only one element out of ten in the total drivepower system for the fan. To optimize \n efficiency, all the elements in the drivepower system should be carefully designed.","bbox":{"left":0.117647,"top":0.538023,"width":0.75684,"height":0.039150999999999936}},{"text":"A high efficiency drivepower system for a fan and duct system should normally include all the following:","bbox":{"left":0.117647,"top":0.594841,"width":0.7557370000000001,"height":0.020212000000000008}},{"text":"1. Efficient Duct System \n The duct system should be designed using an optimization tool such as life-cycle costing. In addition, a \n very careful analysis should be made of the actual volume of air required for the application. Excessive \n air flows result in extra costs both in the initial design and in the electricity costs. \n The horsepower requirements of ducts increases inversely as the fifth power of the diameter of the \n ducts. Thus a round duct system that was undersized in diameter by 50% would require 3100% percent \n more power to deliver the same amount of air!","bbox":{"left":0.117647,"top":0.63272,"width":0.76403,"height":0.13384800000000008}},{"text":"2. Fan Wheel and Casing \n The fan wheel and casing must be carefully chosen. In many applications, backward curved fans are the \n most efficient designs. Inlet and outlet conditions are also very important to minimize unnecessary losses.","bbox":{"left":0.117647,"top":0.784235,"width":0.7641979999999999,"height":0.058091000000000004}},{"text":"3. Fan Belts \n Fan belts are important. Conventional belts lose about 4% to 10% of the energy supplied. Cogged V-","bbox":{"left":0.117647,"top":0.859992,"width":0.747951,"height":0.039152000000000076}}],"images_bbox":[],"images_bbox_not_text_overlap":[]}