PURPOSE: To form a machine room in small size, prevent virtual decrease of capacity of a storage battery in a power interruption time rescue operation device and further to provide inexpensiveness of a total unit.

CONSTITUTION: By mounting a power interruption time rescue operation device 8 to a balance weight 4 on which a linear motor 5 is mounted, a storage battery is given vibration to remove a bubble between electrodes, and space in the periphery of the battery is widened to eliminate a countermeasure of hydrogen gas, generated from the battery, and a power interruption time control cable and further to reduce the balance weight 4 by the amount of weight of the power interruption time rescue operation device 8.