A valve operating machine includes a base having a housing thereon. A motor, and a planetary gearbox are mounted within cavities in the housing. A motor gear, a planetary input gear and an idler gear are mounted within a separate cavity. The motor gear is mounted for rotation with a motor shaft of the motor and the planetary input gear is mounted for rotation with a planetary gear spindle of the planetary input gear. The idler gear is engaged with the motor and planetary input gears. An output socket is connected to the planetary gearbox for connection to a key that is used to exercise a valve.