| 摘要 |
PURPOSE:To shorten the brake distance of a cage during the occurrence of failure in operation and to improve safety by detecting a high harmonic component, generated by an inverter, through a band-pass filter, and generating an emergency stop command when a content of the high harmonic wave component is abnormal. CONSTITUTION:The central frequency of a band-pass filter 16 is set to, for example, a carrier angular frequency Wp, and only a Wp component of an inverter output voltage can be detected. In which case, as far as an elevator control device is normally operated, a cage is in a seating region, and a comparator 17 is not operated while a seating region detecting signal 20 is 1. However, when failure in operation occurs during running in the seating region and the angular frequency Wp component is increased to a value higher than a reference voltage Vref, the comparator 17 is operated and an output signal 17a is 1, and since the cage is in a seating region, a seating region detecting signal 20 is also 1. Thus, an AND gate 19 is operated to issue an emergency stop command 19a, resulting in operation of an electromagnetic brake 7 to stop the cage. |
