摘要 |
An alternating current having a variable voltage and frequency which is converted by an inverter is supplied to an induction motor for driving an elevator so that a speed command value is decreased and the output frequency of the inverter is decreased at the energy saved operation. Thus, energy saved operation may be accomplished without adversing the efficiency even if the speed of the cage is decreased. Since the output voltage of the convertor is increased simultaneously with this, the power factor is improved so that saving in energy is furthermore enhanced. |