The present disclosure relates to a wheel built-in power system for an electric golf bag trolley, including a motor, and a worm wheel engaged with an output worm of the motor, a spindle of the worm wheel being connected to a hub of any wheel of the electric golf bag trolley. The wheel built-in power system for an electric golf bag trolley of present disclosure is small in size and light in weight, and can be installed in wheels of an electric golf bag trolley, thereby effectively reducing the size of the electric golf bag trolley after being folded, facilitating movement and storage.

A brake for a motor includes a fixed-side engaging plate fixed to a motor shaft; a movable-side engaging plate coaxially opposed to the fixed-side engaging plate along the direction of a center axis; and a self-holding type solenoid that moves, in the direction of the center axis, the movable-side engaging plate to a halt cancelation position separated from the fixed-side engaging plate and a halt position where engagement with the fixed-side engaging plate occurs. When the motor is halted, the solenoid is driven to move the movable-side engaging plate from the halt cancelation position to the halt position. The movable-side engaging plate which has reached the halt position is mechanically engaged with the fixed-side engaging plate, and the motor shaft is forcibly halted.