An employee was attempting to clear what he believed to be a clogged blower chute from the spin trimmer. As he was shaking the chute to clear it, the chute disconnected from the blower unit. He pulled a rolling ladder to the unit and then attempted to reconnect the chute to the blower. His left hand slipped and entered the motor where the impeller blades struck and amputated the fingertips of his index, middle, and ring fingers.