The working principle of the motor can cause unbalanced magnetic pull (UMP) between stator and rotor unavoidably. Previous research about nonlinear vibration excited by UMP was focused on supported traditional mechanical bearings or gas bearings. However, levitation is particular due to low rigidity provided active bearing (AMB). amplifies in resonant zone further excites electromagnetic force,...

Copyright 2005 by Helena Johansson. All rights reserved. Readers may make verbatim copies of this document for non-commercial purposes by any means, provided that this copyright notice appears on all such copies. Abstract Technical, allocative, and economic input efficiency scores were estimated for an unbalanced panel of Swedish dairy farms, using data envelopment analysis (DEA) and the stocha...

Abstract There are various methods to produce iron based nano crystalline magnetic alloys. Among these methods, mechanical alloying is one of the most important. In this research, nano crystalline Fe85Si10Ni5 soft magnetic alloy was synthesized by mechanical alloying. The effect of alloying time on phase constituents and magnetic properties of the produced powders was investigated, by X-ray di...

The existing imbalance compensation strategies for magnetic suspension motors mainly focus on the mass unbalance force, ignoring effects of unbalanced magnet pull (UMP). This paper studied vibration mechanism and strategy suspended permanent synchronous motor (PMSM) under influence UMP. Firstly, an analytical model flux density was established based equivalent circuit method, then expressions U...

As the rotational speed of conventional rotor systems supported by oil-film bearings has increased, vibration problems such as oil whip and whirl have become apparent. Our group proposed use active magnetic (AMBs)/bearingless motors (BELMs) to stabilize these systems. In a system, measuring variable stiffness damping bearings, current-force displacement-force parameters AMBs/BELMs, residual unb...

This paper deals with electromagnetic design and 2-D (two-dimensional) magnetic field analysis of novel low force ripple linear switched reluctance (LSR) motor. The configuration that has been presented here has a higher number of rotor poles than stator poles, and the purpose of this configuration is to improve the force ripple, which is the weak point of LSRMs. In order to illustrate the ...

Hard magnetic SrFe12O19 (SrM) nanoparticles were synthesized by a facile sonochemical reaction. The magnetic nanoparticles were then added to acrylonitrile-butadiene-styrene, polystyrene, polycarbonate, and poly sulfone to make magnetic nanocomposites. The magnetic properties of the samples were also investigated using an alternating gradient force magnetometer. The strontium ferrite nanop...

A virtual zero power (VZP) method was used to reduce the consumption of hybrid magnetic bearings (HMBs) in left ventricular assist devices (LVADs). The mathematics HMB system LVAD established, and stability analyzed with a proportional-derivative (PD) controller. unbalanced forces on rotor can be identified by output voltage PD controller, together negative stiffness permanent magnet, suspended...

A multiphysics asynchronous electric machine model based on the angular approach is developed in this paper by adding interaction between Unbalanced Magnetic Pull and rotor center radial displacements to reinforce electro-magneto-mechanic fields couplings. The novelty of proposed lies also calculating instantaneous speed shaft therefore tackling problems non-stationary operating conditions. Thi...