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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
01 Aug 2000
TL;DR: In this paper, a control unit is arranged for a synchronous motor formed of a rotor provided with a magnet, and a drive method selecting unit is used to select an optimum drive method for the current rotation speed based on the information stored in the rotation-speed-vs-efficiency table unit.
Abstract: A control unit is arranged for a synchronous motor formed of a rotor provided with a magnet. The control unit includes a 180°-conduction drive unit for performing 180°-conduction drive of the synchronous motor, a 120°-conduction drive unit for performing 120°-conduction drive of the synchronous motor, a rotation speed calculating unit for calculating the motor rotation speed, a rotation-speed-vs.-efficiency table unit storing an efficiency relative to a rotation speed of the motor, and a drive method selecting unit for selecting an optimum drive method for the current rotation speed based on the current rotation speed and information stored in the rotation-speed-vs.-efficiency table unit. Thereby, the synchronous motor performs 120°- or 180°-conduction drive in accordance with the current rotation speed to achieve the drive with an optimum efficiency.

62 citations

Journal ArticleDOI
TL;DR: In this paper, a weighted pendulum-type electromagnetic generator for harvesting energy from a rotating wheel was proposed, which can match up with the rotational frequency of the wheel at any speed at any angle and angular velocity.
Abstract: This paper proposes the system design of a weighted-pendulum-type electromagnetic generator for harvesting energy from a rotating wheel Different from the traditional energy-harvesting device, the natural frequency of the suitable weighted pendulum, which oscillates due to periodic change of the tangential component of gravitational force, can match up with the rotational frequency of the wheel at any speed In addition, the pendulum oscillates at a large angle and angular velocity so as to generate a large amount of power The physical model of the pendulum was first constructed and the equation of motion was then derived via the Lagrange method Then, the models of power generation were derived by using Faraday's law of induction and the Lorentz force law The nonlinear dynamic behaviors were discussed considering the characteristic length, variable electromagnetic damping, and wheel rotation speed Finally, an experimental rig was constructed to verify the correctness of numerical results The suitable weighted pendulum combined with coils and magnets has demonstrated the power generation of several hundred micro-Watts in the experiment

62 citations

Patent
08 Dec 2010
TL;DR: In this paper, a predictor predicts a future trajectory of the drop of the rotational speed of the crankshaft of an internal combustion engine based on information associated with a drop in the speed of a crankhaft, and a determiner determines a timing of the driving of the starter based on the future trajectory.
Abstract: In a system for driving a starter with a pinion so that the starter rotates a ring gear coupled to a crankshaft of an internal combustion engine to crank the internal combustion engine during a drop of a rotational speed of the crankshaft by automatic-stop control of the internal combustion engine, a predictor predicts a future trajectory of the drop of the rotational speed of the crankshaft based on information associated with the drop of the rotational speed of the crankshaft. A determiner determines a timing of the driving of the starter based on the future trajectory of the drop of the rotational speed of the internal combustion engine.

61 citations

Patent
30 Nov 1989
TL;DR: In this paper, a power generating system consisting of a fluid driven rotor, a generator, and a transmission assembly for coupling the rotor to the generator is described, where the transmission assembly is controlled by an hydraulic circuit which comprises a valve which in a first state prevents flow of operating fluid through the circuit and in a second state permits such flow.
Abstract: A power generating system comprising a fluid driven rotor, a generator, and a transmission assembly for coupling the rotor to the generator. The transmission assembly is controlled by an hydraulic circuit which comprises a valve which in a first state prevents flow of operating fluid through the circuit and in a second state permits such flow, whereby in the first state torque is transmitted from the rotor to the generator with substantially zero slip, and in the second state the assembly slips so as to permit the rotational speed of the rotor to increase relative to the rotational speed of the generator and maintain a substantially constant torque at the generator.

61 citations

Journal ArticleDOI
TL;DR: In this article, a 10MW single-stage SCO 2 working fluid was designed and the unsteady three-dimensional flow field inside the blade passages was assessed by software CFX to obtain the desired parameters of the turbine with maximum total static efficiency.

61 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023539
20221,195
2021522
2020773
20191,092
20181,138