Patent ID: 6568485
Filing Date: 2003-05-27
Classification: E21B

Abstract:
A drilling motor and motor control apparatus for sensing motor stall and for opening a drilling fluid by-pass channel, to divert at least part of the drilling fluid stream that otherwise flows through and provides power for the drilling motor, when the drilling motor rotor speed is less than a preselected amount, the apparatus comprising:a) a drilling motor, drilling fluid powered and provided with a tubular rotor, with means at both ends for attachment to drilling string components; b) a housing arranged to function as a serial length element of a drill string extending upward from said drilling motor, and having a generally central opening; c) rotational speed sensing means, situated in said housing, responsive to said rotational speed of said drilling motor, to produce a first output signal when said motor rotor speed sensed is below said preselected amount; d) valve actuator means arranged to move in response to said signal; e) a by-pass valve, responsive to said move, to open in response to said move a valve means; and f) a fluid by-pass channel, associated with said by-pass valve, to divert drilling fluid to reduce the drilling fluid power delivered to said drilling motor.