نتایج جستجو برای: jeffcott rotor

تعداد نتایج: 14135  

This paper suggests novel sensorless speed estimation for an induction motor (IM) based on a stator current model reference adaptive system (IS-MRAS) scheme. The IS-MRAS scheme uses the error between the reference and estimated stator current vectors and the rotor speed. Observing rotor flux and the speed estimating using the conventional MRAS technique is confronted with certain problems relat...

2012
H. Molavi

A Rotary Disc Contactor with inner diameter of 9.1cm and maximum operating height of 40cm has been used to investigate break up phenomenon. Water-Toluene, Water as continuous phase and Toluene as dispersed phase, was selected as chemical system in the experiments. The mentioned chemical system has high interfacial tension so it was possible to form big drops which permit accurate investigation ...

2017
Gaëtan Didier Eric Ternisien Olivier Caspary Hubert Razik G. Didier E. Ternisien O. Caspary H. Razik

In this paper, a new technique to detect broken rotor bars in polyphase induction machines is presented. Like most techniques, we employ the Fourier Transform of one stator current to make detection. But where the other methods use the Fourier Transform modulus, we propose an alternative approach by analyzing its phase. As shown by results, the Fourier Transform phase allows to detect one broke...

2015
Di Li Zhihong Lu Xiang-jian Chen

In this article, a dynamic model of a six degrees of freedom (6 DOF) Eight-Rotor MAV (micro aerial vehicles) is derived on the basis of the Newton-Euler formalism. The derivation comprises determining equations of the motion of the Eight-Rotor MAV in three dimensions and approximating the actuation forces through the modelling of aerodynamic coefficients and electric motor dynamics. For Eight-R...

2014
M. Jannati N. R. N. Idris M. J. A. Aziz

Speed sensorless vector control of 3-phase induction motor under open-phase fault (faulty 3phase induction motor) based on Indirect Rotor Field-Oriented Control (IRFOC) is proposed in this paper. To ensure high performance FOC of induction motor drives, the estimation of the rotor speed is necessary. However, the algorithm used to estimate the rotor speed for a 3-phase induction motor cannot be...

1995
R. BARBIER J. MEYER

A nonrigid rotor model is developed from the two-parameter quantum algebra U qp (u 2). [This model presents the U qp (u 2) symmetry and shall be referred to as the qp-rotor model.] A ro-tational energy formula as well as a qp-deformation of E2 reduced transition probabilities are derived. The qp-rotor model is applied (through fitting procedures) to twenty rotational bands of superdeformed nucl...

Journal: :Aviation, space, and environmental medicine 1993
J S Crowley S L Geyer

Rotor blade injuries are an inherent hazard of helicopter operations. To determine the recent incidence of rotor blade injuries in the U.S. Army, a review of accident records (1972-91) was conducted. Crash-related injuries were not included. During the study period, there were 24 blade strike injuries (12 involving the main rotor), 11 (46%) of which were fatal. Comparison with previous reports ...

2007
Jonathan Kao Xiaolin Wang John Warren Jie Xu Daniel Attinger

A steady fluid flow, called microstreaming, can be generated in the vicinity of a micro-bubble excited by ultrasound. In this paper, we use this phenomenon to assemble and power a microfabricated rotor at rotation speeds as high as 625 rpm. The extractible power is estimated to be of the order of a few femtowatts. A first series of experiments with uncontrolled rotor shapes is presented, demons...

2012
Sergiu Ivanov Mihai Radulescu

In heavy duty drives in the range of hundreds kW, like cement and minerals industries, wound rotor induction motors are used. Important users make use of hundred of such drives, summing hundreds of MW. This type of motors have technical capabilities to easily operate at variable speed. Despite this simple capability, the large amount of losses which occur at low speeds determine the users to us...

2012
S. Grouni R. Ibtiouen M. Kidouche O. Touhami

Induction machine models used for steady-state and transient analysis require machine parameters that are usually considered design parameters or data. The knowledge of induction machine parameters is very important for Indirect Field Oriented Control (IFOC). A mismatched set of parameters will degrade the response of speed and torque control. This paper presents an improvement approach on roto...

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