Rotational speed

About: Rotational speed is a research topic. Over the lifetime, 23327 publications have been published within this topic receiving 151696 citations. The topic is also known as: speed of revolution & revolution rate.

A turbine driven electric power production system and a method for control thereof

Abstract: A turbine (2) driven electric power production system (1), - said turbine (2) arranged for being driven by a fluid (3) having a fluid speed (v) varying in time, - said turbine (2) connected to a hydrostatic displacement pump (6) further connected to a hydrostatic displacement motor (8) as part of a closed loop hydrostatic transmission system (7), - said motor (8) arranged for driving an electrical generator (9) supplying AC power (10) at a frequency (fg) near a given desired frequency (fdes), characterized by a closed loop system arranged for controlling a volumetric displacement (13) of the hydrostatic motor (8), comprising - a fluid speed meter (11m) arranged for producing a speed signal (11s) representing a speed (v) of said fluid (3), and - a rotational speed meter (12m) arranged for providing a rotational speed signal (12s) representing a rotational speed measurement (ω) of said turbine (2), - a motor displacement control system (15) for continuously receiving said speed signal (11s) and said rotational speed signal (12s) and arranged for calculating a control signal (16), - a volumetric displacement control actuator (17) on said hydrostatic motor, arranged for receiving said control signal (16) for continuously adjusting a volumetric displacement (d) of said hydrostatic motor (8) for maintaining a set turbine tip speed ratio (tsrset) and thereby providing an improved power efficiency of the power production system (1) during fluctuations in said fluid speed (v).

Method for optimizing the rotational speed of cooling fans

Abstract: A method for controlling cooling fans for variable electrical loads. A cooller monitors cooling fan output, ambient temperature and the electrical load. The controller then matches the fan speed and resulting cooling to the existing electrical load and ambient temperature. As a consequence, fan speed is maintained at a minimum necessary to sustain appropriate cooling levels. This minimizes the generation of structureborne and airflow noise.

Variable valve timing apparatus

Abstract: In the case where an intake valve has its phase in a first region between a most retarded angle and CA(1), the rotational speed of relative rotation between an output shaft of an electric motor and a sprocket is reduced at a reduction gear ratio R(1) to change the phase of the intake valve. In the case where the intake valve has its phase in a second region between CA(2) and a most advanced angle, the rotational speed of relative rotation is reduced at a reduction gear ratio R(2) to change the phase of the intake valve. As long as the rotational direction of relative rotation is the same, the phase of the intake valve is changed in the same direction for both of the first region between the most retarded angle and CA(1) and the second region between CA(2) and the most advanced angle.

Method and apparatus for operating vacuum cleaner

Abstract: Method and apparatus for operating a vacuum cleaner in which by detecting a rotational speed of a variable speed fan motor adapted to give a suction force to the cleaner and its change range, the choking state of the filter and the state of the cleaned surface are discriminated, and a speed command of the fan motor is corrected on the basis of the result of the discrimination, and the comfortable cleaning can be performed by the optimum suction force.