绕线式电机运行中的保护

１问题的提出我厂３８０ｋＷ／６ｋＶ电机配套的ＫＧＸＡ—２２００控制柜电气原理如图１。在该电路中,对电机进行了欠压、过载、短路保护。欠压保护由欠电压继电器１ＹＪ、２ＹＪ来完成;过载保护由过电流继电器１ＬＪ、２ＬＪ来完成;短路保护由三个高压熔断器来完成。...     

智能控制算法在电机控制中的应用

随着中国经济的快速发展,智能化的进程也不断加快,电动控制系统应用也越来越广泛。大到工业智能化的生产线,小到孩子玩的电动玩具都离不开电机。采用先进的智能控制方法,调整电机的控制方式,我们可以实现提高电机的运行性能,减少电能的消耗,使电机工作在理想的工作状态,对我们日常的生产和生活有着重要的意义。     

关于电动机优先控制方式的探讨

在目前水泥、矿渣等工业自动化控制系统中,根据控制权限的优先级,经常用到两种电动机控制方式：机旁优先控制方式（也称作就地优先控制方式）和中控优先控制方式（也称作远程优先控制方式）。对于前者,已被大家所熟悉和广泛应用,对于后者,很多电气人员很陌生,但是其应用场所越来越多。本文结合笔者在实际工程中的应用和经验,重点讨论中控优先控制方式的具体实现方法和各自特点,并根据它们之间的区别对适合的应用场所给出建议。     

LOGO230R在开炼机电机控制中的应用

近年来 ,随着小型程控器的广泛应用 ,具有可编程功能的SIMENSLOGO愈来愈受到人们的青睐 ,其采用逻辑功能块组合编程 ,具有输出点额定电流大、可实现远程ASI总线通信和价格低廉等优点。我公司采用开炼机混炼胶料 ,驱动电机为绕线式电机 ,此种电机要求轻载带频敏启动 ,运行中负荷变化较大 ,因此设备采用过流继电器保护。其启动过程为 :接通电机主绕组的接触器 1C ,二次绕组利用频敏无级升速 ,8s后电机速度基本达到同步转速 ,2C吸合断开频敏启动器 ,电机进入正常运转状态。若电机超负荷 ,过流继电器GL动作 ,切断电机供电回路 ;若遇特殊…     

螺旋输送泵电机提速设计与应用

0 引言 河南省焦作坚固水泥有限公司水泥一厂熟料生产线,原螺旋输送泵电机容量为P_e=90kW,电压U_e=380V,极数2P=8,额定转速n_e=750r/min。因产量提高,其输送量不能满足生产工艺要求,需将电机转速提高至n_e=970r/min。若换新电机投资较大。我们采用将原电机改极数的办法完成了提速任务。     

粉煤灰的计量与控制

粉煤灰是以燃煤为燃料发电的火力发电厂排出的一种工业废渣,由于其自身具有一定的火山灰质特性,因此粉煤灰已作为活性混合材料广泛应用于水泥生产过程。由于粉煤灰是容重只有０７ｔ／ｍ３、水分＜１%的极细粉末,因而粉煤灰具有易流动的物理特性。在水泥生产过程中,对粉煤灰的计量与配比控制具有一定的难度。我厂在生料配料和水泥配料中均使用了粉煤灰,以下根据我厂的使用经验谈一谈水泥厂对粉煤灰的计量与配比控制。１粉煤灰固体流量计计量与控制系统简介我厂水泥工段有两个粉煤灰库,最初设计使用两台固体冲击流量计量机构,控制仪表共用一台…     

采用变频调速控制与阀门控制水泵电机节电效果分析

介绍了水泵电机采用变频调速控制节电的原理,在保持阀门阻力不变的前提下,通过调整水泵电机的转速改变管网的流量从而可降低加大阀阻力时阀门所消耗的无用功。其节电原理同亲适用于风机类电机。     

窑尾电收尘器故障分析及处理

随着当今国内外对环境质量要求的提高,水泥行业对烟尘排放的排放要求也越来越严格。而电收尘器作为一种高效烟气净化设备,运转维护成本低,更能很好地适应高温及有腐蚀性气体,在水泥生产线中起到至关重要的作用,特别是在窑尾、窑头温度高,粉尘量大的生产区域。     

Systematic Assessment of Chemokine Signaling at Chemokine Receptors CCR4, CCR7 and CCR10

Chemokines interact with chemokine receptors in a promiscuous network, such that each receptor can be activated by multiple chemokines. Moreover, different chemokines have been reported to preferentially activate different signalling pathways via the same receptor, a phenomenon known as biased agonism. The human CC chemokine receptors (CCRs) CCR4, CCR7 and CCR10 play important roles in T cell trafficking and have been reported to display biased agonism. To systematically characterize these effects, we analysed G protein- and β-arrestin-mediated signal transduction resulting from stimulation of these receptors by each of their cognate chemokine ligands within the same cellular background. Although the chemokines did not elicit ligand-biased agonism, the three receptors exhibited different arrays of signaling outcomes. Stimulation of CCR4 by either CC chemokine ligand 17 (CCL17) or CCL22 induced β-arrestin recruitment but not G protein-mediated signaling, suggesting that CCR4 has the potential to act as a scavenger receptor. At CCR7, both CCL19 and CCL21 stimulated G protein signaling and β-arrestin recruitment, with CCL19 consistently displaying higher potency. At CCR10, CCL27 and CCL28(4-108) stimulated both G protein signaling and β-arrestin recruitment, whereas CCL28(1-108) was inactive, suggesting that CCL28(4-108) is the biologically relevant form of this chemokine. These comparisons emphasize the intrinsic abilities of different receptors to couple with different downstream signaling pathways. Comparison of these results with previous studies indicates that differential agonism at these receptors may be highly dependent on the cellular context.     

变频调速的应用

从设计及应用角度介绍变频器在化肥行业中的应用和控制方案     

Adipose Tissue-Derived CCL5 Enhances Local Pro-Inflammatory Monocytic MDSCs Accumulation and Inflammation via CCR5 Receptor in High-Fat Diet-Fed Mice

The C-C chemokine motif ligand 5 (CCL5) and its receptors have recently been thought to be substantially involved in the development of obesity-associated adipose tissue inflammation and insulin resistance. However, the respective contributions of tissue-derived and myeloid-derived CCL5 to the etiology of obesity-induced adipose tissue inflammation and insulin resistance, and the involvement of monocytic myeloid-derived suppressor cells (MDSCs), remain unclear. This study used CCL5-knockout mice combined with bone marrow transplantation (BMT) and mice with local injections of shCCL5/shCCR5 or CCL5/CCR5 lentivirus into bilateral epididymal white adipose tissue (eWAT). CCL5 gene deletion significantly ameliorated HFD-induced inflammatory reactions in eWAT and protected against the development of obesity and insulin resistance. In addition, tissue (non-hematopoietic) deletion of CCL5 using the BMT method not only ameliorated adipose tissue inflammation by suppressing pro-inflammatory M-MDSC (CD11b⁺Ly6G⁻Ly6C^hi) accumulation and skewing local M1 macrophage polarization, but also recruited reparative M-MDSCs (CD11b⁺Ly6G⁻Ly6C^low) and M2 macrophages to the eWAT of HFD-induced obese mice, as shown by flow cytometry. Furthermore, modulation of tissue-derived CCL5/CCR5 expression by local injection of shCCL5/shCCR5 or CCL5/CCR5 lentivirus substantially impacted the distribution of pro-inflammatory and reparative M-MDSCs as well as macrophage polarization in bilateral eWAT. These findings suggest that an obesity-induced increase in adipose tissue CCL5-mediated signaling is crucial in the recruitment of tissue M-MDSCs and their trans-differentiation to tissue pro-inflammatory macrophages, resulting in adipose tissue inflammation and insulin resistance.     

智能马达控制中心系统在PTA装置的应用

结合化工厂PTA装置应用实例,介绍了智能马达控制中心系统的配置、功能,并总结了智能马达控制中心系统的优点与特点。     

智能型电机保护控制器在沙特TAHAMAH水泥厂5000 t/d熟料线中的应用

主要介绍了新型智能型电机保护控制器SIMOCODE pro 3UF7的工作原理、主要功能、应用实例及常见问题.该装置是一种灵活的模块化电机管理系统,用于低压性能范围内的恒速电机;它优化了DCS和电机起动器之间的连接,提高了设备可用性,使系统的起动、运行和维护费用大大降低.     

基于Profibus现场总线技术的电动机控制和保护装置M102-P

全面介绍了基于Profibus-DP现场总线的ABB公司开发的M102-P电动机控制和保护装置及其主要功能和参数设置;并详细介绍了该装置在巴西MZBA公司3000t/d熟料生产线自动控制系统中的实际应用.     

电能质量综合治理和电机系统节能改造

在炼胶、压延、挤出等直流用电设备以及钢丝帘布生产线上进行动态无功补偿和谐波治理,应用动态电压补偿器消除电压波动以及瞬间暂降,保证生产的经济安全性。供配电网络改造后,更换13台S7变压器,大大减少变压器损耗。采用高效节能变极启动无滑环绕线转子异步电动机,替代现有电机。对热水循环泵等采用电机功率控制器,保证节电系统在任何情况下都能自动保持峰值电机效率,使电机效率达到最高。