Patent ID: 7588124
Filing Date: 2009-09-15
Classification: B66B

Abstract:
1. A speed control method of an elevator-purpose inverter in which an induction motor is controlled in an acceleration manner, a constant speed manner and a deceleration manner by an open loop control type inverter; and when an elevator passenger car reaches a deceleration starting position located at a constant distance from an arriving floor position, the elevator passenger car is decelerated in a constant deceleration speed in the deceleration control manner, the speed control method comprising the steps of: previously calculating an elevating distance when the elevator passenger car is decelerated from a reference frequency up to a leveling frequency in a constant deceleration speed, when the induction motor is stopped; driving the elevator passenger car in a constant speed at an intermediate frequency so that the previously calculated distance becomes equal to an elevating distance when the elevator passenger car is decelerated at the constant deceleration speed from an arbitrary frequency up to the leveling frequency so as to adjust the elevating distance; and automatically decelerating the elevator passenger car at the constant deceleration speed up to the leveling frequency.