| Abstract |
One of possibilities of increasing efficiency of induction machines is lowering supply voltage when load torque is much less than nominal 3/4 energy sawing work. Energy saving work brings about reduction of energy consumption, lowering the temperature of windings, increasing reliability and the effective period of the machine operating. Thanks to reducing temperature of the isolation system the induction cage machine can carry higher overload torque without risking the isolation overheating. It is also possible to carry overload for longer period of time than in case of work with nominal flux. Thermal effect of energy saving work depends on thermal properties of the induction machine, which are different in case of a machine with outside ventilation and without additional ventilation. This paper is devoted to the comparison of the thermal effect of energy saving work on the motor with outside ventilation and without additional ventilation. The variable frequency of supply voltage was taken under consideration. The results of experimental investigations and computer simulations are presented for four-pole induction cage machines with the rated power of 2,2 kW and 3 kW. |
