Abstract: An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.

Abstract: An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.

Abstract: An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.

Abstract: An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.

Abstract: An exhaust fan assembly is provided for expelling contaminated air from a building. The assembly includes a plenum, a fan assembly attached to the plenum, and a windband mounted on top of the fan assembly. The fan assembly is constructed of cylindrical outer and inner walls which define a bearing chamber and surrounding annular space. A fan driven by a shaft extending downward from the bearing chamber draws exhaust air from the plenum and blows it up through the annular space to a nozzle at the top of the fan assembly.

Abstract: A method and apparatus for detecting a failure in the speed sensing system of a rotating shaft prime mover. The control system for the rotating shaft prime mover includes a speed sensing system for measuring the rotational speed of the shaft, a speed feedback system for providing actual rotational speed, and a monitoring system for monitoring the speed sensing system. The monitoring system detects loss of speed signal and overspeed conditions. The speed pickup sensing system includes at least a first, second and third speed sensor. The monitoring system senses with the speed pickup sensors the rotational speed of the shaft to provide signals representative thereof. It selects between the first and second speed signal the signal representative of the actual rotational shaft speed to produce a primary speed signal. The system compares the primary speed signal to the third speed signal for producing a speed feedback fault signal when the primary signal deviates from the third signal by a predetermined value.

Abstract: The invention is practiced by providing a plurality of turbine-driven systems each producing an output proportional to a respective control signal, means for generating a respective first output signal for each of the turbine-driven systems proportional to a respective first system-output indicating parameter, means for generating a respective error signal for each of the turbine-driven systems proportional to any deviation of a respective second system-output indicating parameter from a respective complementary portion of the combined second system-output parameters of the systems, and means for generating the respective control signal of each of said turbine-driven systems and proportional to any deviations of respective ones of the first output signal and the error signal from a respective predetermined reference value of said first parameter, whereby a predetermined relationship of the individual outputs of the turbine-driven systems is maintained.

Abstract: Some power plants may produce both power and process steam as output products and may be referred to as cogeneration power plants. This type of power plant may include at least one extraction type steam turbine in order to conveniently output process steam. Sometimes the available power plant steam supply is insufficient to satisfy both load demand and process steam requirements whereupon it may be desirable to prefer load demand over process steam requirements. The present invention is a control system for electronically implementing that preference.

Abstract: The disclosure sets forth trip circuitry for a rotating shaft machine which includes redundant overspeed protection and means for testing the overspeed protection circuit while the machine remains in operation. Moreover, further protective circuitry is provided for detecting a failure in the speed sensing system. The overspeed protection and the speed sensing failure circuit are each connected to a relay system which may actuate a trip servo valve to a closed position.

Abstract: In a prime mover control system, control over the prime mover is dependent, in part, upon the validity of a reference signal to the control system. Circuitry is provided between a reference signal generator and the control system whereby under normal conditions the reference signal to the control system is the same as the output of the reference signal generator. However, if the reference signal generator output becomes invalid, then a stored reference signal may be substituted for the reference signal generator output by switching from a first signal channel to an alternate second signal channel, each channel selectably interconnecting the reference signal generator and the control system.

Abstract: A speed control system for a fluid driven prime mover, for example, a turbine wherein the speed of the prime mover is controlled by the positioning of at least one fluid inlet valve. The inlet valve is positioned by a valve operator responsive to an output voltage from the speed control system. The output voltage is directly proportional to the phase difference (error) between a variable reference digital pulse train input representing a desired speed and a feedback digital pulse train input representing the actual prime mover speed. During steady-state operation, prime mover load changes will first cause a phase difference between the reference input and the feedback input whereupon a corrective output voltage is immediately applied to the inlet valve operator prior to the occurrence of an actual speed error.