Concepts for sensorless position control of induction motor drives rely on anisotropic properties of the machine rotor. The built-in spatial anisotropy is detected by injecting a high-frequency flux wave into the stator. The resulting stator current harmonics contain frequency components that depend on the rotor position. Models of the rotor saliency serve to extract the rotor position signal u...

This paper describes a speed sensorless vector control method of the torque for cost-effective parallel-connected dual induction motor fed by a single inverter. A natural observer with load torque adaptation is employed to estimate the speeds of the same rating induction motors connected in parallel and fed by a single inverter. The speed difference between the two induction motors for unbalanc...

The aim of this study was to evaluate the impact of a novel crank system on laboratory time-trial cycling performance. The Rotor system makes each pedal independent from the other so that the cranks are no longer fixed at 180°. Twelve male competitive but non-elite cyclists (mean ± s: 35 ± 7 yr, Wmax = 363 ± 38 W, VO2peak = 4.5 ± 0.3 L·min(-1)) completed 6-weeks of their normal training using e...

This paper presents the study of a single-phase synchronous motor with permanent magnets (PM) using some computer programs. This motor type is used especially in household applications, and it has a low power. It is known that PM synchronous motors have a great advantage consisting in the lack of rotor losses. For this motor the starting problem has been solved performing a variable air gap und...

Acoustic emission transducers were used to study the brush/rotor interface of a homopolar motor as a function of design parameters such as speed and load. The results indicate that acoustic emission is well suited for in situ monitoring of brush wear and rotor conditions, and for analyzing the tribological phenomena occurring at the brush/rotor interface. r 2007 Elsevier Ltd. All rights reserved.

This paper presents a parameter study for optimum rotor geometrical parameter combinations of a refrigeration helical twin screw compressor with four commonly used lobe combinations and five different length/diameter ratios and wrap angles. The volumetric and indicated efficiencies of the compressor are important. So also are other factors such as rotor deflection, bearing load, bearing life an...

BECKMAN stressing. ESP allows rotor speed to be reduced automatically before precipitation can occur. Since the time required for gradient formation decreases with faster rotor speeds, this approach results in more rapid separations. In general, for fixed angle rotors, rotor speed is limited by the need to avoid precipitation of the gradient salt at the bottom of the tube, where the concentrati...

In this paper, we present a novel technique to estimate the position of the rotor of a switched reluctance motor by observing the characteristics of the vibration of the stator during the motor operation. This removes the need of the shaft position sensor which is known for its unreliability and problems associated with its application. Vibration in switched reluctance motors is generated mainl...

The effects of variation of blade torsion frequency on rotor performance and structural loads are investigated for a 1/rev active flap rotor and baseline rotor (no active control). The UH-60A four-bladed articulated main rotor is studied at a high-speed forward flight condition. The torsion frequencies are varied by modifying the spanwise torsional stiffness of the blade and/or the pitch link s...

In this paper, stator resistance and speed estimation for a vector controlled induction motor drive taking saturation into account is presented. A mathematical dynamic model of an induction motor as influenced by magnetic circuit saturation is presented. Moreover, a modified structure of indirect vector controller scheme is proposed which involves the saturated value of the magnetizing inductan...