Speed control apparatus for elevator

摘要

A speed control apparatus for an elevator is so constructed that an operating period of time is limited on the basis of a predetermined current command value or an output from a detector for detecting current to be supplied to an induction motor, thereby to render a load time factor of the induction motor a predetermined value or less and to maintain at or below a permissible value a temperature rise value based on a quantity of heat generated by a winding of the induction motor. Thus, the induction motor is prevented from burning even when the induction motor is operated at low speed in, for example, a manual operation mode for installation, maintenance and inspection, or the like.