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.

Engine control apparatus

Abstract: An engine control apparatus controls an engine rotational speed to a target rotational speed by using a detected input side transmission rotational speed of a manual transmission as the target rotational speed upon detecting a clutch pedal depression amount during shifting being equal to or larger than a first prescribed depression amount, which is equal to or larger than a depression amount corresponding to a clutch disconnect position. The engine rotational speed is controlled to the target rotational speed by using the smaller of a computed transmission rotational speed (based on vehicle speed and gear ratio using a shift position) and the detected input side transmission rotational speed, upon detecting the clutch pedal depression amount during shifting being smaller than the first prescribed depression amount and larger than a second prescribed depression amount, which is smaller than the depression amount corresponding to the clutch disconnect position.

Microstructural evolution and mechanical properties of refill friction stir spot welded alclad 2A12-T4 aluminum alloy

Abstract: Refill friction stir spot welding (RFSSW) was applied to join the 2A12-T4 aluminum alloy successfully, and effects of the tool rotational speed on weld formation, microstructure evolution and mechanical properties of the RFSSW joint were investigated in detail. There existed macrostructure characteristics of bonding ligament and hook associated to the plasticized metal flow in the joint. The microstructure of the joint exhibited variations in the grain size, precipitates distribution and substructure in the width direction. A softened region existed in all the RFSSW joints and its formation could be attributed to the coarsening and dissolution of the S precipitates. Liquation cracks associated to the localized melting of S were observed in the stir zone of the joint produced at the highest rotational speed. The tensile-shear properties of the RFSSW joints were dependent on the hook geometry, distribution of the bonding ligament and hardness of the stir zone. With increasing the rotational speed from 900 to 1300 mm, the hook height increased, the bonding ligament at the weld periphery got more dispersed and the hardness of the stir zone decreased. The optimized RFSSW joint was obtained when the rotational speed was 1300 rpm, and the corresponding tensile-shear failure load was 10,030 N. Two different fracture modes, i.e. the shear fracture mode and shear-plug fracture mode, were identified in the tensile-shear tests.

Wind turbine generator and method of controlling the same

Abstract: An object of the present invention is to, if a frequency decrease has occurred in a power system, avoid a trip in a wind turbine generator and reliably contribute to recovery of the frequency of the power system. The present invention provides a wind turbine generator that, if a predetermined frequency decrease that requires PFR has occurred in the power system, calculates a marginal active power based on the difference between a predetermined rotational speed lower limit value, which is obtained by providing the parallel-off rotational speed with a predetermined margin, and a measured value of the shaft rotational speed, and generates an active power command value based on the marginal active power.

Differential apparatus with additional speed increasing gear and speed decreasing gear selectively engageable with a single output shaft

Abstract: A differential apparatus comprises: a differential gear (1) rotatably housed in a left end within a carrier case (3); a speed increasing mechanism and reducing mechanism (31) housed within the carrier case (3) in such a manner as to be adjacent to the rear differential apparatus (1), having a speed increasing mechanism (37) for increasing a rotational speed and a speed reducing mechanism (39) for reducing the rotational speed of the input gear (33) connected to a differential case (11) in a parallel manner; a speed increasing and reducing clutches (53) mounted to the carrier case (3) and for connecting and disconnecting the rotation from the input gear (33) which are arranged in a plane crossing to axes of output shafts (21,23) in parallel.

Study on finishing characteristics of magnetic abrasive finishing process using low-frequency alternating magnetic field

Abstract: This paper describes a new ultra-precision magnetic abrasive finishing (MAF) process using alternating magnetic field. The process principle and the finishing characteristics are described. Specifically, the effects of finishing parameters such as cutting fluid, rotational speed of magnetic pole, and current frequency on change in material removal and surface finish are investigated respectively. Experimental results indicate that neat cutting oil is more suitable for this processing, which can obtain higher material removal and smoother finished surface compared with water-soluble cutting fluid and silicone fluid. The finishing force and material removal are gradually increasing with the increase of rotational speed of magnetic pole. It is confirmed that the angle variation of magnetic particles is decreasing with the increase of current frequency, and the few nanometer surface can be acquired in the condition of low frequency.