Active magnetic bearings enable contactless operation and can therefore be used for supporting rotors spinning at high speeds. However, the rotational speed in conventional reluctance-force-based magnetic bearing topologies is limited, which is mainly due to high rotor losses and limited force control bandwidths. In this paper, a prototype of a self-bearing motor is presented, which overcomes s...

The permanent magnet synchronous machine with an external rotor is the most important device for high performance electrical drive systems in particular for hybrid electric vehicles. With such an application, the machine will operate in a wide speed range and on the other hand with very fast changing loads in both motor and generator operational modes. The paper discusses finite element analyse...

This paper deals with implementation of the field-oriented control strategy in an induction machine. The rotor flux orientation strategy tends to give true decoupling control, where the control reference frame rotates at synchronous speed and is held by the rotor flux. Simulation results show that the machine presents a high dynamic performance similar to those of DC machines. This approach pre...

Numerical stability analysis for aerostatic bearings was performed to obtain optimized design parameters small submillimeter millimeter range diameter cylindrical rotors. Such rotors are used in nuclear magnetic resonance (NMR) application rotate sample around an axis inclined by magic angle (54.74o) relative the field direction at rotational frequencies of about 100 kHz (magic-angle spinning, ...

Cross-polarized magic-angle-spinning NMR (CPMAS-NMR) techniques are assumed to be only semi-quantitative in the assessment of carbon distribution in humic substances or natural organic matter, due to a number of interferences such as spinning side bands (SSB) in spectra, paramagnetic species in samples, and low or remote protonation of aromatic carbons. Fast rotor spin rates or direct polarizat...

Dynamic Nuclear Polarization (DNP) experiments transfer polarization from electron spins to nuclear spins with microwave irradiation of the electron spins for enhanced sensitivity in nuclear magnetic resonance (NMR) spectroscopy. Design and testing of a spectrometer for magic angle spinning (MAS) DNP experiments at 263 GHz microwave frequency, 400 MHz (1)H frequency is described. Microwaves are...

The mechanisms of defocusing and refocusing of spin order in extended dipolar coupled nuclear spin systems are investigated by experiments on static and on rotating solids. It is demonstrated that polarization or coherence echoes are possible also under magic-angle sample spinning. The dipolar interactions, averaged by the spinning, are recovered by rotor-synchronized multiple-pulse sequences. ...

Pelleting inactivates SODle viruses and aggregates other dispersed :material. Methods for separation should be developed in which desired particles are always kept in suspension. Rotors that cODlbine continuous-flow centrifugation with isop"ycnic banding can achieve this effect. In our SySteDl a liquid density gradient is set up in a spinning rotor next to the wall in each of 4 sector-shaped cO...

Abstract: – In this paper a new rotor field orientation control of six phase induction machine is proposed. The machine has two three phase windings spatially shifted by 30 electrical degrees. The dynamic model of the machine is based on the three two dimensional orthogonal subspaces. The proposed method uses a simple estimator for identifying rotor flux and its orientation. To eliminate the ex...

In this research paper, the performance of an air-cored axial flux permanent magnet synchronous generator is evaluated for low speed, direct drive applications using 3D finite element modeling and experimental tests. The structure of the considered machine consists of double rotor and coreless stator, which results in the absence of core losses, reduction of stator weight and elimination of cog...