Patent ID: 7816804

Claim:
A power supply device comprising: a power supply capable of supplying an electric power to a power supply line; a drive circuit arranged between said power supply line and a motor for driving and controlling said motor; a power storage device connected to said power supply line and arranged in parallel to said power supply; a switch device electrically connecting said power storage device to said power supply line in a closed state; and a control device controlling an open/close operation of said switch, wherein said power storage device includes: a relay circuit arranged to be connected in series to said switch device on a current path being formed of said power supply line and said power storage device when said switch device is closed, and a first connection member being externally removable, being attached to said relay circuit for connecting contacts of said relay circuit together via a resistance element, and being removed from said relay circuit for disconnecting the contacts of said relay circuit from each other, and said control device closes said switch device in response to attachment of said first connection member to said relay circuit when a power supply voltage of said power storage device is equal to or lower than a predetermined threshold.