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The variation of stator winding turns will directly affect the key parameters of a motor, such as winding resistance and winding reactance, which further affect the steady-state performance of the motor. In order to get excellent steady-state performance from line-start permanent magnet synchronous motors (LSPMSMs) under different load powers, taking an 11 kW LSPMSM as an example, the finite element method (FEM), combined with the steady-state phasor diagram and torque angle characteristic, are used in this paper for the optimal design of the stator winding turns of the prototype. The correctness of the model is verified by comparing the experimental data with the calculated data. First, the influences of different stator winding turns on the no-load, back-induced electromotive force (EMF), as well as on inductance and overload ability are studied, and the variation mechanism is obtained. In addition, from the perspective of the torque angle characteristic, the influence of the change in synchronous inductance caused by the number of turns on the steady-state power angle is studied. Second, the variation of the current and power factors with turn number is obtained by studying the steady-state power angle and end voltage. Based on the coupling relationship between the no-load back EMF and the power angle, the mechanism of non-linear variation of current and power factor is revealed. Finally, the variation of the number of turns on the core loss and eddy current loss is analyzed under various operating conditions, and the variation mechanism is revealed, based on the armature reaction theory.

The typical metal transfer mode in conventional underwater wet flux cored arc welding (FCAW) delivers large droplet repulsive transfer with low frequency. The process stability and the weld quality are seriously deteriorated with significant spatter and frequent arc extinctions. It is thought the repulsive forces applied on droplets can be reduced by rapidly decreasing the welding current, making the droplets sag and oscillate. A novel underwater pulsecurrent FCAW was proposed to periodically regulate the forces applied on droplets. The experimental system was developed with specially designed pulse current and reliable arc length control. Visual and electrical signals were collected simultaneously to study the process features. It was found that the maximum droplet diameter decreased to less than 5 mm; the temporary arc-extinguishing frequency decreased significantly; there was almost no short-circuit transfer and surface-tension transfer; and the stability of the welding process was significantly improved.

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Background Enhancer has been recognized as an important driver whose genetic alterations contribute to disease progression. However, there is still no easy-to-use tools to identify pathogenic enhancers, allowing for deciphering functional influence of genetic variants on enhancer. Results We developed a user-friendly one-stop shop platform, named inferring pathogenic enhancer with variant (IPEV), only requiring variants as input, to quickly infer the pathogenic enhancers that harbor variants affecting their activities. Results of IPEV are explored in an interactive, user-friendly web environment, which is designed to highlight the most probable pathogenic enhancers and their target genes. Furthermore, IPEV provides intuitive visualizations of how a variant affects the corresponding enhancer activity by mediating TF binding changes. Conclusions IPEV is specially designed to prioritize the potentially pathogenic enhancers with genetic variants, and provides intuitive visualizations how a variant affects the corresponding enhancer activity by mediating which transcription factor binding changes. The use of IPEV does not require any specialized computer skills. We believe that IPEV will be useful in interpreting non-coding variants by the inferring pathogenic enhancers. It is freely available at http://biocc.hrbmu.edu.cn/IPEV/ or http://210.46.80.168/IPEV and supports recent versions of all major browsers.

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The application of an inverter is becoming more and more widespread in the surface-mounted permanent-magnet synchronous motor (SMPMSM). A large number of voltage harmonics can be generated by the inverter. The electromagnetic torque, loss, and air-gap magnetic density of the SMPMSM are affected by voltage harmonic. To analyze its influence, taking a 3 kW 1500 r/min SMPMSM as an example, a two-dimensional transient electromagnetic field model is established. The correctness of the model is verified by comparing the experimental data with the calculated data. Firstly, the finite element method is used to calculate the electromagnetic field of the SMPMSM, and the performance parameters of the SMPMSM are obtained. Based on these parameters, the influence of voltage harmonic on motor performance is analyzed quantitatively. Secondly, the influence of the voltage harmonic on the air-gap magnetic field is analyzed, and the influence degree of the time harmonic on the air-gap magnetic field is determined. At the same time, torque ripple, average torque, and loss are studied when the different harmonics orders, amplitudes, and phase angles are contained in voltage, and the variation is obtained. Finally, the variation mechanism of eddy current loss is revealed. The conclusion of this paper provides reliable theoretical guidance for improving motor performance.

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