变压器直流偏磁电流监测技术研究

在介绍变压器直流偏磁电流对变压器影响的基础上,对开展直流偏磁电流监测的相关技术进行了研究,并设计了一种光电型变压器直流偏磁电流监测装置,该设计在电气上完全切断了过电压及各种干扰的传播路径,能有效保证监测装置工作的稳定性、可靠性。     

弧焊变压器焊接时触电的原因分析及防范措施

阐述了使用弧焊变压器施焊时产生触电的原因,并提出了安全使用弧焊变压器焊接时的措施。希望焊接人员摒弃错误的观念及麻痹思想,高度重视安全用电,确保人身安全。     

两台变压器的经济运行对节能降损的影响分析

随着能源的日益短缺,各行各业对节能降损越来越重视.在电力行业中,配网损耗中的60％是由变压器贡献的,因此实现变压器的经济运行对用电企业的节能降损具有重要要义.以江门地区某工厂为实例进行了计算论证,针对性的提出了两台同容量和不同容量变压器经济运行的方法.     

A cross-validation of the NIOSH limits for manual lifting

The psychophysical, biomechanical, and physiological criteria used in establishing the NIOSH limits for manual lifting were cross-validated against the data published by different researchers in the subject literature. Assessment of the 1991 NIOSH lifting equation indicated that: (1) NIOSH-based limits are significantly different from the psychophysical limits in the (i) low and high frequencies of lift, and (ii) small and large horizontal distances; (2) NIOSH limits are highly correlated with the data of Snook and Ciriello (1991) in the low frequency range, with the Recommended Weight Limit (RWL) protecting about 85% of the female population and 95% of the male population; (3) the 3·4 kN limit for compression on the lumbosacral joint cannot protect the majority of the worker population on the basis of damage load concept; and (4) energy expenditure limits used in development of the RWL index can be sustained by 57 to 99% of worker population when compared to the physiological limits based on previous fatigue studies. Results of the cross-validation for psychophysical criterion confirmed the validity of assumptions made in the 1991 NIOSH revised lifting equation. However, the results of cross-validation for the biomechanical and physiological criteria were not in total agreement with the 1991 NIOSH model     

Plenary Session: Operation Functions in Vehicle Control Anthropoteehnik in der Fahrzeugfuhrung

Abstract

Manual-handling-related injuries remain a fairly high and constant proportion of all injuries at work in Australia. To assist in reducing the number and severity of these injuries, the Occupational Health and Safety Manual Handling Regulations 1988, came into effect in February 1989 in the state of Victoria. The regulations do not specify any weight limits but require employers to ‘assess and control risks arising from manual handling activities in workplaces’. The regulations are supplemented by a code of practice to provide practical guidance in the three stages of risk identification, assessment and control. There is a risk-identification checklist and the assessment is based on the NIOSH formula and factors by means of a calculated weight table. Risk control establishes a priority order of job redesign, mechanical aids and specific training. Practical examples illustrate the processes, and the possible control options. The positive role that ergonomics can play in solutions and improving productivity is discussed.     

Carrying and spine loading

The advantages and disadvantages of different methods of carrying objects on spine loading are still not fully understood. Previous studies have either examined the effects of carrying using physiological measures or examined isolated spine segments using biomechanical models. Additionally, most studies have been restricted to only a small number of carrying conditions. Very few studies have attempted to examine the various factors influencing spine loading together. To improve understanding of interacting factors on carrying, this study assessed the lumbar spine loads of 16 subjects as they assumed six styles of carrying at two weight levels and two activity levels (walking vs. standing). Concurrent with each trial, a subject-specific biomechanical model was used to assess spine forces over the full lumbar spine. Most carrying methods in the trials resulted in relatively low levels of spine loading. Anterior/posterior (A/P) shear loading was the only spine-loading dimension that reached biomechanically meaningful levels. Two carrying conditions, with bins carried in front of the body, significantly increased A/P shear compared with other carrying styles. This increase appeared to be due to the greater moment arms occurring in these conditions. Many of the other carrying styles produced A/P shears that were similar to those observed when carrying nothing at all. Of all the tasks, the backpack carry characteristically produced especially low spine loads. The findings of the study suggest that to achieve optimal carrying in terms of spine loading, loads should be positioned close to the body, even when carrying relatively light loads.     

隔离变压器在UPS中的设置

隔离变压器在UPS中不作为标准配置产品,所以在UPS选购时,须根据实际的需求额外提出。隔离变压器的设置位置不同,起到的作用也会不同。     

利用红外测温诊断技术发现电流互感器内部缺陷

在电力系统中，电力设备的质量直接关系到电网的运行安全，而由于电力设备内部缺陷而引起的设备事故对电网的危害更大。应用红外测温诊断技术可以及时发现电力设备缺陷特别是内部缺陷，使设备故障得到及时的消除，避免电力系统事故的发生。     

配电变压器的熔断器保护

分析了限流熔断器和负荷开关-熔断器组合电器在环网供电单元和预装式变电站中的应用形式与特点,介绍了熔断器选择的基本原则.     

变压器中铜箔的应用现状及发展趋势

介绍了铜箔在变压器应用的现状,概述了箔式绕组变压器的种类、特点及经济性.