| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power supply device for electric hoists capable of maintaining the life of an electricity-accumulating device for a long time and acquiring an energy-saving effect for a long period of time by suppressing the reduction in capacity. <P>SOLUTION: The power supply device includes the electricity-accumulating device 17, connected to a DC circuit 12 via a parallel circuit of a switching element A and a charging resistor 22. A control means is provided to carry out the following operations: When a lifting electric motor 15 is regenerated, the switch element A is closed to accumulate the regenerative electric power into the electricity-accumulating device 17 from the DC circuit 12. In power running, the accumulated electric power of the electricity-accumulating device 17 is supplied to the lifting electric motor 15. When an accumulated voltage V<SB>C</SB>of the electricity-accumulating device 17 is less than a DC voltage V<SB>D</SB>of the DC circuit 12, the switching element A is opened to accumulate electric power into the electricity-accumulating device 17 through the charging resistor 22. When the accumulated voltage V<SB>C</SB>reaches the DC voltage V<SB>D</SB>, the switching element A is closed and it is determined from the stop time of the lifting electric motor 15 whether or not the electricity-accumulating device should be put into a rest mode. When the rest mode is determined, a braking switching element 19 is closed to supply a current of the accumulated electric power of the electricity-accumulating device 17 to a braking resistor 20. <P>COPYRIGHT: (C)2010,JPO&INPIT |
