共查询到20条相似文献,搜索用时 140 毫秒
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0引言直流电动机长期工作时,换向器表面一般会形成薄薄的一层氧化膜,它会提高耐磨性,增加电刷与换向器的接触电阻,使换向过程比较理想,但在实际工作中换向器往往因运行条件的不同而出现多种多样的状态。为了保持良好的运行状态,提高电机的运行效率,换向器表面必须维持稳定而良好的氧化膜。所谓换向器表面的良好状态就是不产生过大的换向火花,磨损正常。换向器表面的磨损随运行时间的 相似文献
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我厂BE卷烟包装机的主驱动采用的是直流电动机调速控制系统,由于直流电动机的结构复杂,其定子上有激磁绕组产生主磁场,对功率较大的直流电动机常常还装有换向极,以改善电动机的换向性能。直流电动机的转子上安放电枢绕组和换向器,直流电源通过电刷和换向器将直流电送入电枢绕组并转换成电枢绕组中的交变电流,即进行机械式电流换向。复杂的结构限制了直流电动机体积和重量的进一步减小,尤其是电刷和换向器的滑动接触造成了机械磨损和火花,使直流电动机的故障多、可靠性低、寿命短、保养维护工作量大。因此考虑将其主驱动的直流电动机调速控… 相似文献
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稀土永磁无刷直流电动机的应用与市场前景 总被引:2,自引:0,他引:2
永磁无刷直流电动机用电子换向替代了电刷和换向器,可以实现高性能、高可靠性、长寿命、免维护的目的。永磁无刷直流电动机是集交流电动机和直流电动机优点于一体的机电一体化产品。 相似文献
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安川电机公司八幡厂的生产线上采用很多机械手,制造各种交、直流电动机。兹介绍直流电动机换向器的加工及主极、换向极焊接方面的例子。1.换向器加工的自动化(1)目的每个直流电动机的换向器由大约100张换向片构成,过去云母片下刻、升高片焊接等用手工操作,加上产品的形状、大小、片数不一,很难实现自动化。但是,这次用机械手进行工序闯工件的搬运装卸,实现了完全自动化。 相似文献
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1 .概况无刷电动机一般是指无电刷和换向器(或集电环 )的电机。以前交流电动机采用鼠笼转子 ,与直流电动机相比调速困难 ,运行过程难以控制。而直流电动机虽控制灵活 ,调节电压即可线性调速 ,但我们知道一般转子绕组要用碳刷、换向器 ,这样维护困难 ,噪声振动大。现代电子技术的发展 ,采用电子换向电路替代碳刷与换向器 ,而开发出新一代无刷电动机。永磁无刷直流电动机与一般直流电动机工作原理和特性相同 ,而其组成是不相同的 ,其构成与永磁式步进电动机 (或可以说是永磁同步电动机 )相似 ,其转子是由永久磁铁组成 ,定子上有着多相绕组 ,并… 相似文献
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直流电动机在运行中,电枢绕组中各个槽内元件(导体)的电流方向,是随着电枢的旋转而不断变化的,这种电枢绕组电流改变方向的过程,称为换向。而实现其中电流改变方向的部件称为换向器。根据国家标准,将电机的换向火花大小分成五个等级。对连续工作的直流电动机,其换向火花一般不应超过3/2级,因换向火花过大,可能将电刷烧焦,灼伤换向器,使电动机不能正常运行;另外,也会使电动机产生较大电磁噪声,成为电子设备的干扰源。 相似文献
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Permanent magnet brushless drives 总被引:1,自引:0,他引:1
Chan C.C. Xia W. Jiang J.Z. Chan K.T. Zhu M.L. 《Industry Applications Magazine, IEEE》1998,4(6):16-22
The purpose of this paper is to present an optimal efficiency control scheme for constant power operation of phase decoupling (PD) PM brushless DC motor drives. The key is to adaptively adjust the advanced conduction angle to minimize the system losses for a given operation point in the constant power region. The strategy for constant power operation of PD PM brushless DC motor drives is exemplified using a 5-phase 22-pole PD PM brushless DC motor. In the sections that follow, the newly-developed optimal efficiency control technique is then illustrated. Then, after describing the corresponding implementation, both computer simulation and experimental results are presented, and some conclusions are offered 相似文献
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ABSTRACT This paper presents a practical method for operation of a semi-converter-fed DC motor drive at the point of maximum efficiency while maintaining any particular torque-speed load point. Design and operation of an economical, microprocessor-based adaptive controller used to retrofit a commercially available SCR drive for minimum loss operation of a DC motor is described. Experimental and simulation results are presented in graphical forms, giving comparison of overall drive system efficiencies between loss minimization adaptive control and conventional constant field current operation for a standard-efficiency DC motor with a 7½ hp rating for both separately excited and shunt connected configurations. The greatest potential for energy savings is found to exist for the case of light load at low speeds. 相似文献
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This paper describes the design and implementation of a 5 kW microcomputer-controlled thyristor bridge rectifier (TBR) that has been introduced in the undergraduate electric machinery laboratory at Montana State University. The unit is used in an independent experiment on the operation of the TBR and its control by a microcomputer, as well as for controlling the applied voltage to the armature of a DC motor for controlling its speed. Since the operation of the motor speed controller is based on control of the TBR, it was noticed that the addition of the TBR experiment will help students better understand its operation as well as the operation of the DC motor speed controller experiment. Experimental results are presented on the operation of the rectifier, and evaluation of the experiment is reported 相似文献
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Saneifard S. Prasad N.R. Smolleck H.A. Wakileh J.J. 《Education, IEEE Transactions on》1998,41(2):159-164
The fundamental equations governing the operation of a DC motor are straightforward and are well presented in most undergraduate curricula, usually in a required energy conversion or electrical machinery class at the junior level. The physical implications of the equations regarding device behavior, and the need for speed control, are easily understood. Furthermore, students can readily develop a mental picture of the physical motor and its response. Speed control of a DC motor represents an ideal application for introducing the concepts of fuzzy logic. Once the fundamentals of fuzzy logic have been presented to the students, their application to the speed control problem can be easily demonstrated. The paper shows how a commercially available fuzzy logic development kit can be applied to the theoretical development of a fuzzy controller for motor speed, which represents a very practical class of engineering problems 相似文献
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他励直流电机电枢并联运行时负载不能自动均衡,必须设计相应的负载均衡电路进行调节.详细分析了调节他励电机励磁的办法,解决了胜利九号钻井平台他励直流电机电枢并联负载均衡问题. 相似文献
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基于DSP的直流伺服电机调速 总被引:3,自引:0,他引:3
讨论了直流电机的各组成部分;介绍了脉宽调制技术的工作原理。运用自动控制理论和DSP技术,借助CCS开发环境,用DSP54XEVM板的硬件控制电机的不同运动状态。实验结果表明:直流伺服电机系统结构简单,调速性能稳定、可靠,且易于维护和改变控制。 相似文献
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本系统用的是一种开关频率较低的PWM晶体管电流型逆变器。在开关模式上分别采用了次谐波调制和低次谐波消除技术,电机电流在整个调速范围内具有较小的谐波分量。控制电路采用了恒转差频率控制,确保电动机运行在机械特性的非稳定区域,从而避免了电机磁通进入饱和状态。此外,本文提出的过电压吸收装置可以有效地消除晶体管换向时由直流电抗器产生的尖峰电压。最后给出了实验结果。 相似文献