Choosing the motor for a certain application determines its initial cost and also the cost of operation. The use of an insufficient power motor can cause an improper operation of the system coupled to it, resulting in poor productivity. It can also result in premature damage to the engine and, on the other hand, a power motor above the required, in addition to a higher initial cost, leads to low performance, low power factor and reduced service life. All these consequences are not desirable from an economic and technical point of view. In a wider context, the correct application and selection of motors are of great importance today because of the increasing cost and energy shortage that occurs not only in Brazil but also abroad.
As statistics show, about 60 to 70 percent of all electrical energy produced is converted to mechanical energy by electric motors. In industrial sectors this percentage reaches 80% and in commercial sectors at 50%. Measures to reduce consumption, whether they are restricted to the industrial scope, or are they of greater scope necessarily pass through the reduction of the consumption of electric motors, that can have a significant value considering its useful life, that is of 15 to 20 years.