低压铸造机压力检测单元改进

<正>GIMA低压铸造机压铸轮毂时是通过向封闭的低压保温炉充入干燥压缩空气,压缩空气将铝水从升液管压入轮毂模具中充型而成。充型过程中,铸造机控制系统需要根据压力检测单元反馈的信号(检测炉内压缩空气压力),实时调整进入保温炉的干燥压缩空气量。压力检测单元由零压开关、超压开关和压力传感器组成。零压开关监测炉内零压力时的压力。自动状态下,铸造机在打开模具之前,由于密闭保温炉和封闭模具组成的封闭体压力不可能绝对为零,因此出厂时通过拨动零压开关的调节旋钮将其压力设定为4.5 kPa     

改进翻车机轨道衡数据处理技术

对铁路货车轨道衡自动称重系统的来车方向辨识,轨道衡断波处理,零点误判,接近开关故障判断等问题进行技术改进,重新编写程序,解决丢数据、亏吨问题。     

天车故障的诊断

桥式天车主回路、控制回路大致相同,其中控制回路如图1。该控制电路可分3部分:(1)零位保护回路,包括端子“13”、QA、K_(xo)、K_(so)、K_(?)和端子“17”(我厂天车中未装QA按钮,靠紧急开关JK起动主接触器XC)。(2)联锁保护回路,包括端子“17”、JK(紧急开关)1MK、2MK(门开关)及电流继电器节点接触器XC线圈和端子“12”。(3)限     

数控机床维修三例

1.CK7940数控车床X轴回零故障 CK7940数控车床,FANUC-OTD系统.使用中,机床偶尔发生X轴回零后,加工的工件在直径上相差12mm,用百分表检查X向丝杠的反向间隙为0.01mm,这么小的间隙不可能造成直径方向那么大的误差.检查X向重复定位精度,在误差范围内,说明机械传动链没有问题.怀疑问题可能出在回零开关上,但用系统诊断画面检查X向回零开关,没有发现问题.再次作回零操作,零点又正常.分析误差值发现,误差正好是丝杠螺距6mm的整数倍.因此判定问题还是产生在回零过程,故对回零程序进行研究.     

西门子数控系统维修(二)第二讲 常见故障及排除方法

一、荧光屏无显示(设备运行一段时间后的黑屏) 　　在使用810T/M的设备中，荧光屏无显示是常见的一种故障，尤其在潮湿气候下，关机较长时间后，更为突出。主要是由于备用电池无电引起的；也有少部分是由于硬件损坏造成的。广大客户所希望的是如何能准确而快速的判断出故障原因。下面以个人遇到和处理该故障的经验，编制了流程图，供大家参考。 　　1.流程图 　　2.流程图说明 　　(1)在机床正常工作时，请将第一讲表1中的Ⅱ/Ⅲ类即系统使用者/机床使用者的数据备份。 　　(2)所有板的插拔都要在断电情况下进行。 　　二、回参考点问题 　　1.回参考点的目的 　　为什么要回参考点呢?不回参考点行不行呢?简单地说，回参考点是为了每次上电开机后，在机床上建立一个唯一的坐标系。尤其当810T/M安装在一般的中档以上机床时，回参考点是必不可少的。对于那些低档数控机床由于功能要求不同亦可不回参考点。 　　2.回参考点的过程 　　　当某一个轴开始回参考点，其接触开关信号有“0-1-0”(在810T/M中是Q108.4为第一轴回零信号，Q112.4为第二轴回零信号…)或者(即1-0-1)的变化后，810T/M的位置环等候从编码器中零脉冲(Zero Mark)的发出。当接到该脉冲信号后再移动2mm的距离该轴停下来，并确认回参考点过程完成，由于在开关信号变化后的零脉冲在机床上是唯一的，所以建立的坐标系是唯一的。 　　3.有时为什么回不了参考点 　　这个问题有两种可能：(1)接近开关坏了。在回参考点的过程中，虽然机床撞了回零挡块，但Q108.4/Q112.4…无信号变化，则回零肯定要失败。解决的办法是让接触开关运动，要使对应的Q108.4/Q112.4等有变化；若无变化须排除相应的故障。 　　(2)虽然Q108.4/Q112.4等有信号变化，但仍未在该停的位置上停下来，则位控环或零脉冲有问题了。请围绕零脉冲的接收问题，检查接收故障所在。 　　4.有时为什么回不准(原点在不同的位置) 　　当你明白了回参考点的过程后，这个问题就相对简单了。这主要是由于回零的接触开关挡块松动变化了(编码器安装在电机上)，或光学读数头松了(光栅尺为位置检测环)，请检查和紧固这两个元件。     

数控车床刀塔原点的调整

美国哈挺COBRA51数控车床如果出现500号报警（刀塔不回原点）时,需重新调整刀塔原点。方法为关机,再重新开机按系统控制开关时,同时按OP和CAN键,直到出现画面后,再执行。在回零方式下（REF）,同时按CYCLE STYING和FEED-HOLD键,将刀塔回零。如果刀塔未回到1号刀位,或没有落下,则执行以下步骤。     

钳工一组“四零”目标

宝钢集团某公司钳工一组休息室的墙报上写着"工作零杂念,安全零违章,检修零失误,材料零浪费"四句话。班组成员们说:"这四句话是用沉痛的教训换来的,是咱们组长带领大家在长年实践中形成的。它已经印在我们心里,落实在我们行动上。"事情是这样的,一次,班组一名员工在主卷机检修后,告诉组长检修完毕,但人仍然在行车大梁上未离开。组长一启动开关,那名员工一声惨叫,组长立即刹车,只见那名员工被大梁挤压住。好在只是轻伤,没造成严重后果。     

YV1600ATC型数控立车换刀故障排除

分析YV1600ATC型数控立车自动方式下进行自动换刀时无法进行的原因，并通过程序提示逐步查找修改设置参数，调整限位开关的机械位置或者修改零脉冲信号的位置错开临界位置，问题迎刃而解。     

关于《XB-10控制箱的节电运行》的一点改进

看了去年第8期上湖南湘乡水泥厂刘喜南同志的《XB-10控制箱的节电运行》一文,深受启发,但美中不足之处是必须在原操作程序中,增加一个手动使转换开关回“零”动作,这样使操作工人一时难以适应,若运行完毕时,忘记手动转换开关回“自动”或“手动”档,会使下次起动难以进行。图为改进后的电气原理图,只要在虚线处加装一只微动开关即可。此微动开关与碳刷提升机连动,当     

一起配电变压器烧毁事故分析

2007年2月，龙江供电所配网部维修一台S7-400／10渗油变压器，扳紧高低压瓷套管、变压器分接开关螺丝，加入约8kg的20^#变压器油。维修结束，依次合上A、C相跌落式熔断器后，听到轻微声音，合上口相熔断器时声音更大，约3s后，变压器油从接缝处喷出。查该变压器表面布满油迹，高低压侧出线套管完好，高低压绕组绝缘测试为零，台区的跌落式开关没有烧断、跌落。     

What types of switching costs to create under behavior-based price discrimination?

We study firms' incentives to create switching costs using a four-period model consisting of two consecutive price-competing stages intervened by options to create switching costs early (before price competition) and late (during price competition). Acknowledging that many real/social switching costs need to be created early while many contractual/pecuniary switching costs are set up late during the competition, we show that firms are better off minimizing real/social switching costs while maximizing contractual/pecuniary switching costs. The results highlight the importance of timing of creation that is embedded in different types of switching costs. We also show that switching costs can actually benefit consumers when firms practice behavior-based price discrimination because consumers can enjoy benefits of deep price discounts without the hassle of actually switching. Therefore, an observed lack of consumer switching should not be immediately interpreted as lack of competition in markets where both switching costs and behavior-based pricing exist.     

When do switching costs make markets more or less competitive?

In a two-period duopoly setting in which switching costs are the only reason why products may be perceived as differentiated, we provide necessary and sufficient conditions for switching costs to lead to higher prices in the first period as well as to higher overall profitability. We show that this happens if and only if switching costs are not too large. We present the only treatment up to date of how switching costs (and only switching costs) affect competition based on the assumption that switching costs differ across consumers, which allows us to illustrate the undesired byproduct of assuming that products exhibit substantial horizontal differentiation. Not only do we draw implications for the classical literature on competition with switching costs, but also for the more recent one that rests upon such an assumption too.     

Securing business-to-business relationships: The impact of switching costs

While the relationship marketing literature acknowledges the importance of switching costs for increasing customer retention, little is known about its relevance in industrial markets. In particular, it is unclear whether switching costs, and associated dimensions, impact on behavioral outcomes of buyer–seller relationships in business-to-business (B2B) markets. In order to contribute to theory development in this important area, our research first explores the dimensions of switching costs for the B2B domain and also tests the relative impact of these dimensions on business customers' actual purchase behavior. Results suggest that switching costs in B2B settings are a multi-faceted construct, including (i) procedural, (ii) financial, and (iii) relational switching costs. Moreover, we find relational switching costs to be most important for securing B2B buyer–seller relationships since they impact a customer's (a) share-of-wallet, (b) cross-buying behavior, and (c) actual switching behavior. While procedural switching costs only influence share-of-wallet, financial switching costs solely impact customer's cross-buying behavior. These findings contribute to a better understanding on how to secure B2B buyer–seller relationships.     

Predicting Household Switching Behavior and Switching Costs at Depository Institutions

This paper uses new survey data to investigate the covariates of self-reported switching costs and switching behavior by deposit account holders. Factors affecting geographic mobility appear to be most important in explaining the duration of deposit relationships. Both younger and older respondents are more likely than others to be at their first bank ever, suggesting a cohort effect in deposit relationships. Households reporting switching costs, net of the benefits from switching, are less likely than others to have stayed with a bank for prices or customer service, suggesting that switching costs may decrease price sensitivity. Switching costs appear more severe for households with high income or education and for households with very low income or minority ethnicity. These findings imply that banking markets characterized by such households may present greater entry costs for new firms.     

Switching Costs in Two‐Sided Markets

In many markets, there are switching costs and network effects. Yet the literature generally deals with them separately. This paper bridges the gap by analyzing their interaction (or ‘indirect bargain’) in a dynamic two‐sided market. It shows that in the symmetric equilibrium, the classic result that the first‐period price is U‐shaped in switching costs does not emerge, but instead switching costs always intensify the first‐period price competition. Moreover, an increase in switching costs on one side decreases the first‐period price on the other side. Policies that ignore these effects may overestimate the extent to which switching costs can reduce welfare.     

Customer capabilities,switching costs,and bank performance

Customers develop switching costs when they invest time and effort to develop capabilities required to optimally use a given product. Such capabilities are likely to be firm specific and cannot be transferred perfectly to competitors' product offerings. Customers who face switching costs are likely to remain with the same firm and consume complementary products that meet their needs. Thus, firms can achieve competitive advantage by exploiting customers' switching costs. In this paper, we hypothesize that the extent to which firms can benefit from customers' switching costs is contingent upon the firms' internal cross‐selling capabilities. We use online banking data to test our hypotheses and find that customers' switching costs contribute to banks' profitability only in the presence of high levels of internal cross‐selling capabilities. Copyright © 2012 John Wiley & Sons, Ltd.     

How Do Switching Costs Affect Market Concentration and Prices in Network Industries?

I investigate the effects of switching costs on the market outcome in network industries using a dynamic duopoly model of price competition in the presence of an outside option. I find that the role of switching costs depends on network effects and the outside option. Without a viable outside option, high switching costs can neutralize the tendency towards high market concentration associated with network effects, but with a viable outside option, switching costs increase market concentration. Furthermore, switching costs lower prices if network effects are modest and there exists a viable outside option, but generally raise prices otherwise.     

Reducing the level of switching costs in mobile communications: The case of Mobile Number Portability

Switching costs are one of the most important economic forces that affect market competition in mobile communications. Both theoretical and empirical studies have shown that switching costs reduce market competition leading to higher prices, lower product and service quality, and lower customer welfare. Given their negative consequences, national regulatory authorities have designed policies aimed at reducing switching costs and fostering competition. One of the most important of these, in the mobile communications industry, is mobile number portability (MNP). The aim of this paper is to investigate the effect of MNP on switching costs in mobile phone services. First, a hierarchical Bayes model is proposed to measure switching costs at the customer level and to investigate the impact of MNP on them. Second, this study examines the drivers of MNP adoption by customers using a binary logit specification. The results reveal that this regulatory policy has significantly reduced the cost of switching and that MNP adoption partially depends on customer-related variables.     

Multi-dimensional analysis of perceived switching costs

The creation of switching costs for customers is an important aspect of strategic planning in today's competitive environment. These costs enable firms to address variations in customer preferences and competitor influence in attempting to gain their customers' loyalty. Although the recognition of the importance of such switching costs has long existed in a variety of contexts, the conceptualization and measurement of the construct is lacking in clarity and consistency. This study proposes that perceived switching costs (PSC) constitute a higher-order construct made up of six dimensions that reflect the customers' perception of the time, effort, and money involved in the switching process. The study also proposes that each of the six dimensions has a distinctive set of antecedents and outcomes. The test of the model is an empirical study in the Spanish insurance sector. The results confirm the validity of the higher-order formative construct of PSC and provide insights for specific strategies to address the perceptions of various customers with regard to switching costs.     

开关电源高频变压器的设计

在无工频变压器的开关电源中,高频变压器的设计是其关键技术。本文首先介绍开关式集成稳压器的分类和开关电源的电路原理,然后重点阐述高频变压器的设计。