Saving energy using energy efficient motors: a case study

India is among the top growing countries in casting and forging units. These units consume a large portion of electrical energy produced in our country. The work presented explores the possibility to minimize the wastage of energy in casting and forging units. A careful study of working of Hammers & Instantaneous load analysis of motors has been carried out to compare with different make equal rating motors. The plant under study had 138 motors of various ratings. The already installed motors have poor efficiency and also operate at poor power factor. There were no efficiency standards for polyphase induction motors. So standard motors were designed with efficiencies high enough to achieve the allowable rise in temperature for the ratings. There is a variation in the efficiency for a given h.p rating from around 74% to 94 %. There is an increasing number of manufacturers who have started making energy efficient motors. We have procured data sheets for these motors and then replaced the existing plant motors with energy efficient motors. Then comparison of standard motors with energy efficient motors based on number of parameters viz. voltage, current, power, power factor has been made.. The costing and payback period for use of energy efficient motors has also been calculated. We have taken various motors already installed in the units and taken readings of rating, Voltage, Current, Power and Power Factor. Then replaced these motors with energy efficient motors and again took the above readings. After this the total tariff was calculated and the payback period was found out. The study reveals that replacing standard motors with energy efficient motors , the total motor load of the plant comes to 804.59 kW as compared to 870 kW of the previous arrangement. Besides leading to cost saving, this has also increased the efficiency of the plant.