平立转换轧机基础的数模振动分析

通过对某钢厂连轧中型钢厂平立转换减速机改造工程设计实例的介绍,提出了平立转换轧机电机置于轧机基础顶部的数模振动分析,可供其他工程参考。     

φ290热轧机程序控制

我厂轧一车间二工场是轧制圆钢和螺纹钢的小型车间。轧机设备布置如图1所示。机架排成两列:第一列为两架φ290轧机,由一部主电机传动,主电机功率为625瓩、735转/分,轧机转速102转/分。第二列为五架φ290轧机,由两部主电机传动,一部主电机为320瓩、490转/分,拖带两架轧机;另一部主电机为630瓩、740转/分,拖带三架轧机,轧机转速为245转/分。轧机的辅助设     

大功率轧机主电机电气传动方案的分析与比较

交流传动调速系统性能已经大大超过直流传动调速系统,交流传动技术在新建的轧机主传动中已经成为主导技术,交流传动系统又分为交 交传动和交 直 交传动两种传动方式,为此本文对交 交变频和交 直 交变频进行了深入的分析和比较,为大功率轧机主电机传动装置的设计选型提供参考。     

热连轧粗轧机速度控制的分析与优化

粗轧机速度控制采用低速咬钢、高速轧制、低速抛钢的可逆轧制模式。因为受限于上下主电机轧制电流差别大,主传动系统的轧制速度不高。分析发现,主传动控制系统以牺牲电流为代价保证上下电机转速平衡。通过在主传动控制程序中引入负荷平衡环节后,使上下传动电机电流差控制在8％以内,同时提高了粗轧机各道次轧制速度,使单卷轧制时间比未提速前节约了8s,提高了粗轧机的轧制节奏。     

冶金轧机主传动交流调速系统的发展及应用

冶金轧机主传动系统作为生产线的核心装备具有装机容量大、系统可靠性高、过载能力强、动态响应快等特点,目前主导的轧机主传动电气控制已由直流系统变为交流系统。介绍并比较了几种轧机传动系统中主要的交流调速方案,对其适用范围和优缺点进行了分析,重点介绍了采用新型可关断电力电子器件的三电平PWM变频调速系统的结构和特点,同时探讨了我国目前大功率轧机主传动交流调速系统的研究和应用现状,为冶金企业大功率轧机主电机传动装置的设计选型提供参考。     

1780mm热连轧R2粗轧主电机止推轴承故障处理浅析

北营轧钢厂1780 mm热连轧自2007年12月投产以来,R2粗轧机主电机传动侧轴承座两侧止推轴承频繁烧损,主电机止推轴承频繁报警并联锁停机,严重影响正常生产,本文对粗轧机主电机止推轴承烧损的原因进行了分析研究,详细介绍了粗轧主电机止推轴承故障处理的过程,并采取了多种措施处理,目前R2粗轧机主电机运转正常,未再发生止推轴承烧损故障。     

连续小型轧机的设计问题

本文从轧机辊径选择、机架布置、机架组成、机架结构、主传动电机的变速方式、速度控制、轧制中的张力控制等方面,列举了各种方案和数据,并提出了小型连续轧机设计参考的方案。     

DCS800传动单元中的DCS Link通讯在轧机传动电机主从控制中的应用

通过对DCS Link通讯的讲解和分析,给出了轧机传动电机间主从控制的一种较好的方式,从而进一步提高轧机的传动控制精度。     

节能型棒材平立转换轧机回转缸液压阀台的开发与应用

论述了控制棒材平立转换轧机回转缸的一种节能型液压阀台的研发与应用.该阀台可以用较低压力的液压站供油,但是能够使棒材平立转换轧机回转缸得到工艺要求的高工作压力.即不需要因棒材平立转换轧机回转缸高工作压力的要求而提高轧区液压站系统压力,也节省了专用液压站,还简化了通常情况下回转缸动作时液压站繁琐的操作程序.能够减少能耗、减少设备投资,减少设备维护工作量和环境污染,以及减少运营成本,并满足快节奏生产的需要.     

平/立转换轧机轧缝调节和错辊现象的分析和改进

平／立转换轧机由于使用的特殊性，对轧机的设计制造及使用要求较高，在现场实际使用中，如果设计制造考虑不周，使用不当，很容易出现问题，从而对产品质量造成更大影响，本文介绍了连轧生产线上进口的平／立转换轧机在现场使用过程中暴露出的几个问题及解决这些问题的措施。     

水平连铸机驱动系统的改造实践

衡阳钢管（集团）有限公司２＃水平连铸机Ⅱ流驱动系统由原先的液压伺服系统改造为变频调速双水冷却慢步电机驱动系统,介绍了新系统的构成及工作原理,并对改造措施及取得的效果都进行了阐述。     

Effect of horizontal vergence on the motor and sensory components of vertical fusion

PURPOSE: To compare motor and sensory capabilities for fusion of vertical disparities at different angles of horizontal vergence in healthy humans. METHODS: Eye movements were recorded from both eyes of 12 healthy subjects using three-axis search coils. The stimulus was a cross (+) (3.4 x 3.2 degrees , vertically and horizontally, respectively) presented to each eye with a stereoscopic display. Vertical disparities were introduced by adjusting the vertical position of the cross in front of one eye. The disparity was increased in small increments (0.08 degrees ) every 8 seconds. Viewing was defined as "near" if there was a horizontal disparity that elicited 6 degrees to 15 degrees convergence, depending on the subject's capability for horizontal fusion; viewing was defined as "far" at 1 degrees convergence. Maximum motor (measured), sensory (stimulus minus motor), and total (motor plus sensory) vertical fusion were compared. RESULTS: In 9 (75%) of 12 subjects the maximum total vertical fusion was more in near than in far viewing. The three who did not show this effect had relatively weak horizontal fusion. For the entire group, the motor component differed significantly between far (mean, 1.42 degrees ) and near (mean, 2.13 degrees). Total vertical fusion capability (motor plus sensory) also differed significantly between far (mean, 1.68 degrees ) and near (mean, 2.39 degrees ). For the sensory component there was no difference between between far (mean, 0.268 degrees ) and near (mean, 0.270 degrees ). As vertical disparity increased in a single trial, however, there was a small gradual increase of the contribution of the sensory component to vertical fusion. CONCLUSIONS: Vertical fusion capability usually increases with convergence. This increase is caused primarily by an increase in the motor component. There is a gradual but small increase in the sensory component as target disparity slowly increases.     

Activity of common marmosets (Callithrix jacchus) in limited spaces: Hand movement characteristics.

The increasing popularity of marmoset monkeys (Callithrix jacchus) in anatomical, behavioral, and electrophysiological studies has called for a detailed analysis of their natural behavior within limited spaces. In the present study, the authors analyzed hand movements during horizontal and vertical progressions in a cylinder. The trajectory of each hand covered the entire cylinder floor during horizontal progressions and the entire cylinder wall during vertical progressions. Different marmosets have different patterns of hand movement. The average maximum angle of hand movements for all marmosets during horizontal and vertical progressions oscillates, although the average over time is constant and similar for both hands, whereas head movements during horizontal progressions become smaller with successive progressions. Another observed difference between rats and monkeys was in the size of head and hand movements at the beginning of each experimental session. During the 1st horizontal progression, all marmosets moved their heads to a greater extent than their hands. This sequential head and hand movement is referred as bistable behavior. The bistable pattern of motor behavior, which was also observed in successive progressions, may be derived from an inherent fear of predators or exploratory interest of a novel environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diazepam eliminates the anxious state induced by amputation of the vibrissae (a model for assessing anxious behavior)

Diazepam (0.5 mg/kg) prevented reduction of motor activity of rats (both vertical and horizontal components) induced by vibrissae amputation. It is suggested that the observed decrease in motility is related to development of a pathologic reaction of anxiety. The method is recommended as a test for anxious behaviour in experiment.     

"Velocity leakage" in the pigeon vestibulo-ocular reflex

The transfer characteristics of the vestibulo-ocular reflex (VOR), and of the semicircular canal primary afferents (SCPAs) that drive it, have been studied in several species. In monkeys and cats, the dominant time constant describing horizontal VOR dynamics (tau hv) is longer than that (tau c) of horizontal SCPAs. This lengthening of the time constant has been attributed to a "velocity storage" mechanism that has been modeled as a positive feedback loop in the VOR pathways. We have studied the transfer characteristics of horizontal and vertical VOR and SCPAs in unanesthetized pigeons. In this species the dominant time constants of both the horizontal and vertical VOR (tau hv and tau vv) are shorter that tau c. This finding indicates that time constants characterizing the lower frequency response of the VOR can be lengthened or shortened depending on the species. We propose that in the pigeon the "velocity leakage" mechanism can be modeled by substituting negative feedback for positive feedback in the model of the VOR pathways. Negative feedback can also account for the further shortening of tau hv and tau vv as VOR gain increases with arousal. Additionally, making the negative feedback loop nonlinear can model the dependency of lower frequency VOR phase on amplitude, and skew in VOR waveforms. Pigeon VOR and SCPA dynamics also differ in their adaptive properties and higher frequency behavior. A predominance of input from highly adaptive SCPAs is proposed to account for the increased adaptation of the vertical VOR as compared with SCPAs overall. A pure time-delay associated with VOR operation can explain the phase lag of the VOR relative to SCPAs at higher frequencies.     

CSP轧机振动和振纹的试验研究

为了找出珠钢CSP热连轧机组在轧制薄规格集装箱板时出现振动的规律和机理,对该机组中间3架轧机的主传动系统扭振、机座系统垂振、抑振措施进行了现场测试,并对带钢(轧辊)振纹和工艺参数、轧机振动之间的关系,振纹形成必要条件等进行了研究.结果表明:F2轧辊振纹频率为14 Hz,是由齿轮座齿轮啮合冲击激起主传动扭振造成的;F3轧辊振纹频率为54 Hz,是由接手弧形齿啮合冲击引发辊系水平振动造成的;F4轧辊振纹频率为78 Hz,是由机座水平系统共振造成的;对F4来说为避免振纹形成,在一定轧速下需谨慎选择工作辊直径.对比试验发现,关闭乳化液和采用高速钢轧辊对振动的抑制有较好效果.     

四辊轧机主传动系统轴向窜动问题分析与改善

通过对 R2 轧机主传动系统轴向窜动问题进行分析,确定轧机上下辊系发生轴向窜动的原因分别是辊缝调整时万向接轴水平长度的变化和轧辊交叉产生的轴向力。通过采取提高主电机轴向阻尼止推装置的阻尼效果以降低扁头套与扁头之间的临界摩擦力以及通过调整下辊系的交叉状态以降低辊间轴向力等措施,使 R2 轧机主传动系统轴向窜动问题得到有效解决,避免了重大设备事故的发生。     

水平松料器布置方式对流场结构的影响

本文就水平松料器的尺寸，布置间距，布置高度对烧结料层中气体流场结构的影响进行了冷态试验研究；确定了松料器的垂直影响范围，展示了尺寸，布置高度，布置间距三者对流场结构的显著影响，认为，只有综合考虑三者的影响才能最大限度地发挥水平松料器改善气流分布，增产，节能的作用。     

汽轮机替代电机拖动烧结主抽风机的探讨

阐述了用汽轮机替代电机拖动烧结主抽风机降低成本的可行性、可靠性,介绍了汽轮机拖动烧结主抽风机系统、汽轮机设计的特殊考虑及其优缺点,分析比较了汽轮机替代电机拖动烧结主抽风机的经济性。采用汽轮机替代电机拖动烧结主抽风机技术成熟,可实现节能降耗的目的。     

2250热连轧R2轧机轴向力生成机理

针对某2250热连轧R2轧机轴向力过大导致传动系统的主电机轴承座和水平轴轴承座移位事故的问题,研制了轴向力在线监测系统并对轴向力进行长期在线监测.从理论上剖析了轧机轴向力生成的主要原因并进行了计算机仿真研究和探讨,得出轴向力的大小与辊系交叉角密切相关.通过减小辊系轴承座与牌坊之间的间隙来控制交叉角的大小,从而可以有效地减小轧机轴向力,这一结果得到现场实验验证.