a method and apparatus for turbine overspeed protection , useful for steam and gas turbines , is disclosed . the apparatus comprises a spring - loaded rod held by a plurality of energized solenoids in an operating position any time the turbine &# 39 ; s shaft rotational speed is less than a trip rotational speed set - point . when the rotational speed reaches the trip rotational speed set - point , both solenoids are de - energized and the spring - loaded rod moves to provide turbine trip . increased reliability of the solenoids is provided by compressing the spring during the resetting of the rod with an additional electromechanical actuator and by using a plurality of solenoids , each of which is able to provide the force required to hold the spring in its compressed state .