| 摘要 |
PROBLEM TO BE SOLVED: To prevent a burning accident of a motor accompanied by fusing of contact points in a mechanical switch. SOLUTION: This hydraulic device is provided with cylinders 21 and 22 for displacing a cargo receiving deck, a pump 23 for supplying fluid into the cylinders, and the electric motor 24 for driving the pump as components. The motor current supplied to the electric motor 24 is controlled with the usage of a semi-conductor switch 3, the motor current is detected by an electric current sensor 4, an electric signal inputted to the semi-conductor switch 3 is varied in accordance with the magnitude of the detected motor current, and the motor current is increased or decreased. Thereby, the mechanical switch can be removed from an electric circuit 8 for supplying the electric current to the electric motor from a power source 7, and the burning accident by fusing of the contact points of the switch can be prevented. COPYRIGHT: (C)2005,JPO&NCIPI
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