Porównanie wskaźników energetycznych przy energooszczędnej pracy silnika klatkowego, realizowanej przez skokową regulację napięcia

Economic effectiveness of the operation of a propulsion system depends on energy indices of motors. Along with the type of operation, the load can vary greatly. Most induction motors operate at load which is considerably lower than their nominal load. Operation at small load or idle run has an adverse effect, when energy indices of the motor, such as power factor and energy efficiency, are very low. There is a need to improve these indices and establish conditions for optimum motor operation. If the motor's load is lower than its nominal load, supply voltage should be lowered to make the energy indices as high as possible. Thus, supplying the motor with voltage which varies depending on the degree of load brings positive results. At nominal load, the motor must by supplied with nominal voltage, however, as the load decreases, the voltage should be accordingly lowered. Lowering the supply voltage will result in decreased energy losses, which are connected with it, as well as increased energy efficiency and power factor. This leads to lower power consumption and thus to saving electric energy. The paper presents transients of current supplied from the mains, the power factor, and motor energy efficiency for various degrees of voltage changes ensuring the motor,s low-energy operation.