Auxiliary Slots Research Articles

Research to the Tension Monitoring Instrument of Bolt and Cable in Multi-Point

Since safety of roadway and steady of rock depend on bolt and cable supporting quality [~[, it is important to evaluate timely bolt and cable supporting quality that monitors tension state of bolt and cable. With separated type design, the monitoring instrument, which is to monitor tension of multiple survey point and separation type Bolt and Cable, is made up of tension of bolt and cable sensor and secondary measuring instrument. This paper focuses on the composition and the basic principle of the tension of bolt and cable sensor structure, the composition of secondary measuring instrument structure and functional partition of the chips and circuit theory of the monitoring instrument. This paper introduces the concrete implementation way and the conditions of usage of the monitoring instrument and introduces the monitor in the application of the auxiliary slot of 22301 working face of Shen Dong coal group Shi Ge Tai ore.

Cogging Torque Modeling and Analyzing for Surface-Mounted Permanent Magnet Machines With Auxiliary Slots

Cogging torque is one of the emphases and difficulties of research on permanent magnet (PM) machines. In this paper, an improved analytical model, based on an exact subdomain model idea and Maxwell stress tensor, is applied for calculating a cogging torque of surface-mounted PM machines with auxiliary slots. It can accurately take account of the interactions between slots and the influence of finite slot depth and can be widely applied to internal/external rotor topology and radial/parallel/segmented-Halbach magnetized machines. The finite-element (FE) method is adopted to validate the proposed model. The results show good agreement in both flux density and cogging torque waveforms. Furthermore, the effects of auxiliary slot parameters on cogging torque are investigated. Conclusions are derived from the analysis and indicate that the analytical model provides a useful tool for PM motor design.

Detent Force Reduction in Permanent Magnet Tubular Linear Generator for Direct-Driver Wave Energy Conversion

In this paper, a quasi-Halbach magnetization structure of permanent magnet tubular linear generator (PMTLG) with bulged stators and auxiliary slots is proposed to reduce the detent force. In the meantime, the detent force for the structure of 9 PM poles 10 winding slots and the conventional one of 8 PM poles 12 winding slots is compared by using Fourier analysis and finite element analysis (FEA). The theoretical and FEA show that 87.18% detent force can be removed through changing the length of the bulged stator. Finally, a prototype is manufactured to verify that the detent force can be reduced efficiently by applying this method.

An FEM-Based Auxiliary Slot Design for an 8-Pole/12-Slot SPM Servo Motor Considering Saturation of Stator Tooth Coronas

This paper studies the auxiliary slot design technique for cogging torque minimization basing on an 8-pole/12-slot SPM servo motor. When the stator tooth coronas are unsaturated, the notching guidance given by analytical method can be testified effective in cutting down the cogging torque by FEM. But when the stator tooth coronas are saturated, the notching guidance is not effective any more. This phenomenon indicates that the saturation of stator tooth coronas has a significant impact on cogging torque. Thus, in auxiliary slot design, saturation effect should be considered; otherwise, counterproductive effects would occur.

직류감쇄시험법에 의한 IPMSM의 인덕턴스 산정

This paper deals with a reduction of cogging torque and estimate of inductance for IPMSM. The flux barriers(Barrier) and the auxiliary slot(Notch) for the reduction of cogging torque was installed for increase of driving characteristic in IPMSM. The cogging torque, driving torque and inductance are analyzed by using FEM(Finite Element Method) and the results of inductance calculation are compared to experimentation ones.

The SPEED System: An Overview of the Appliance and Clinical Performance

The SPEED appliance (Strite Industries Ltd., 298 Shepherd Ave., Cambridge, Ontario, N3C 1V1 Canada), invented by Dr. G. Herbert Hanson in the early 1970s, is a miniaturized self-ligating bracket with an active spring clip. This fully preadjusted edgewise appliance, which is available in both 0.018″ and 0.022″ slot size, has been in clinical use since 1977 and commercially available since 1980. During the past 25 years, the SPEED design has been highly refined. Refinements include the incorporation of a superelastic nickel titanium spring clip for greater precision of tooth movement throughout treatment, a "labial window" that enhances ease of opening the spring clip, and a horizontal auxiliary slot in the bracket body that facilitates segmental archwire mechanics. Although the SPEED bracket is compatible with virtually any archwire selection, specific archwires have been designed to fully exploit SPEED's inherent benefits. These include Supercable (Strite Industries Ltd.), a seven-stranded coaxial nickel titanium archwire, Hills Dual-Geometry archwire (Strite Industries Ltd.), and SPEED archwires. Whether traditional or specialty archwires are used, SPEED, with its highly flexible spring clip, creates a unique mechanical system that is ideally suited for ultra-precise orthodontic tooth movement.

New cogging-torque reduction method for brushless permanent-magnet motors

We present a new design method for reducing cogging torque in brushless permanent-magnet (PM) motors. In our method, the auxiliary slots are put on the pole face of the magnetizing yoke, which results in a not fully magnetized zone (NFMZ) at the PM. Through Fourier expansion of the field and armature functions, the position and shape of the NFMZ that eliminate the cogging torque are found. In an example, we discuss the effectiveness and applicability of the new method.

The effects of the distribution of residual magnetization on the cogging torque and switching signals in permanent magnet (PM) motors

A novel cogging torque reduction method is presented for permanent magnet (PM) motors. The key idea of the method is optimizing the distribution of residual magnetic flux density of the PM by putting auxiliary slots on the pole face of the magnetizing yoke. Through the three-dimensional (3-D) finite-element simulation with edge elements and nodal force method for the motor having eight PM poles and six winding slots, the effectiveness of the presented method is proved. The effects on the switching signal are also investigated.

Influence of machine symmetry on reduction of cogging torque in permanent-magnet brushless motors

We study two methods to reduce cogging torque, both based on the analysis of the rotational symmetry in a brushless permanent-magnet motor. The first one seeks to lower the symmetry in the flux of a conventional motor with asymmetrical magnet distribution. The second one uses auxiliary slots to increase the frequency of the cogging. Analytical calculations have been made to predict the harmonic spectra of the models. Numerical calculations by the finite-element method were carried out. The results support the analytical conclusions. The frequency of the torque pulsation was increased, as predicted. We obtain a peak-to-peak cogging torque reduction of about 85% for each of the two methods. Dynamical calculations show no changes in the mean torque produced. The asymmetrical motor could introduce some ripple due to the EMF shifting.