Topic
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.
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Patent•
21 Dec 2010
TL;DR: In this paper, the rotational speed of a pneumatic hand tool is adjusted in real time to maintain a selected speed level irrespective of exterior parameters affecting the performance of the tool.
Abstract: The rotational speed of a pneumatic hand tool is adjusted in real time to maintain a selected speed level irrespective of exterior parameters affecting the performance of the tool. The apparatus is comprised of a rotational speed sensor installed directly on the tool, a digital microprocessor using control algorithms, and a valve to adjust the flow of air to the tool.
406 citations
TL;DR: In this article, a Savonius rotor wind turbine was tested in the Vought Corporation Systems Division 4.9- x 6.1m Low Speed Wind Tunnel to determine aerodynamic performance.
Abstract: Fifteen configurations of a Savonius rotor wind turbine were tested in the Vought Corporation Systems Division 4.9- x 6.1-m Low Speed Wind Tunnel to determine aerodynamic performance. The range of values of the varied parameters was as follows: number of buckets, 2 and 3; nominal freestream velocity, 7 and 14 m/s; Reynolds number per meter, 4.32 x 10/sup 5/ and 8.67 x 10/sup 5/; rotor height, 1 and 1.5 m; rotor diameter (nominal), 1 m; bucket overlap, 0.0 to 0.1 m. The measured test variables were torque, rotational speed, and tunnel conditions. It is concluded that increasing Reynolds number and/or aspect ratio improves performance. The recommended configuration consists of two sets of two-bucket rotors, rotated 90 deg apart, with each rotor having a dimensionless gap width of 0.1 to 0.15.
381 citations
01 Jun 1983-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the effect of variables such as rotational speed, bed depth, cylinder diameter, particle size, and particle shape on bed motion has been determined, and the scaling of bed behavior with respect to particle size and cylinder diameter requires similarity of Froude number modified by(D/d p)1/2, and pct fill.
Abstract: Slumping and rolling beds have been studied extensively in a continuous pilot kiln and batch rotary cylinders. Solids investigated include nickel oxide pellets, limestone, sand, and gravel. The effect of variables such as rotational speed, bed depth, cylinder diameter, particle size, and particle shape on bed motion has been determined. For a given material, the different modes of bed motion can be delineated conveniently on a Bed Behavior Diagram which is a plot of bed depthvs rotational speed. The scaling of bed behavior with respect to particle size and cylinder diameter requires similarity of Froude number modified by(D/d
p)1/2, and pct fill. Measurements of key variables characterizing slumping and rolling beds have also been made.
372 citations
Patent•
21 Dec 2006
TL;DR: In this article, the authors proposed that the entire rotational speed range of a surgical machine be divided into at least one lower range for low rotational speeds and at least two ranges for higher rotational rates.
Abstract: To improve a surgical machine with an electric motor comprising a rotor and a plurality of motor windings, and with a motor controller for controlling and/or regulating the electric motor so that, in particular, the efficiency of the electric motor can be optimized essentially over the entire rotational speed range, it is proposed that the entire rotational speed range of the surgical machine be divided into at least one lower rotational speed range for low rotational speeds and at least one upper rotational speed range for higher rotational speeds than those in the at least one lower rotational speed range, that the motor controller be so designed that a first controlling and/or regulating method for controlling and/or regulating the electric motor is performable in the at least one lower rotational speed range, and that a second controlling and/or regulating method for controlling and/or regulating the electric motor is performable in the at least one upper rotational speed range.
347 citations
TL;DR: In this article, a simple axisymmetric two-dimensional supersonic solution of a rotating radiation-driven stellar wind from the Friend & Abbott one-dimensional model of the equatorial flow is presented.
Abstract: We present a simple approximation that permits us to obtain the axisymmetric two-dimensional supersonic solution of a rotating radiation-driven stellar wind from the Friend & Abbott one-dimensional model of the equatorial flow. Our solution predicts the formation of a dense equatorial disk if the rotation rate of the star is above a threshold value, which depends on the ratio of the terminal speed of the wind to the escape speed of the star. Along the upper main sequence (earlier than B2), both the observed and theoretical values for this ratio decrease monotonically toward later spectral types. For early O stars, the disk can only form if the rotation speed is in excess of 90% of the critical (breakup) speed
328 citations