Abnormal elevator speed detector

An abnormal speed detector for an elevator system having an elevator car for servicing a plurality of floors, drive means for driving said elevator car at various speeds in a pattern according to a predetermined speed command and speed detector means for detecting the running speed of said elevator car, said abnormal speed detector comprising:

• storage means for storing a set of speed data representing a predetermined abnormal speed pattern as a function of at least one parameter whose value unidirectionally changes after the elevator car starts to run, said abnormal speed pattern including data relating to an abnormality of the elevator speed for all speeds from start to stop thereof;
• means for periodically reading out of said storage means speed data corresponding to a current value of said one unidirectionally changing parameter from said set of speed data in accordance with changes in said parameter value after the start of the run of said elevator car;
• and
• means for comparing the actual speed of said elevator car as provided by said speed detector means with the speed data read out of said storage means to determine if the speed of said elevator car is normal or not.