Redundant overspeed protection for power tools

摘要

An overspeed protection subsystem is provided for a power tool having an electric motor (14). The overspeed protection subsystem is comprised of: a motor switch (16) coupled in series with the motor (14); a motor control module (18) interfaced with the motor switch (16) to control switching operation of the motor switch; and an overspeed detection module (22) that determines rotational speed of the motor (14) and disables the power tool when the rotational speed of the motor exceeds a threshold.