Patent ID: 6344089
Filing Date: 2002-02-05
Classification: B66B,H02K

Abstract:
A drive machine for elevators comprising:an electric motor including a rotatable drive sheave over which a main cable for hanging an elevator cage is wound, a stationary shaft for supporting rotation of said drive sheave and bearing a load applied to said drive sheave by said main cable, a field magnet attached to said drive sheave and comprising at least one pair of magnetic poles, an armature attached to said stationary shaft, facing said field magnet and constituting part of said motor, a field magnet pole detector for detecting a magnetic pole of said field magnet rotating together with said drive sheave, a rotation detector for detecting rotation of said drive sheave with respect to said stationary shaft, detection difference calculating means for detecting a difference between the rotation of said drive sheave detected by said rotation detector and rotation of said drive sheave detected by said field magnet pole detector, and anomaly determining means for determining occurrence of an anomaly when the difference determined by said detection difference calculating means exceeds a threshold value.