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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Systematic Synthesis And Analysis Of Multi-DOF Toggle Mechanisms For Electrical Switches

Deb, Manan 01 1900 (has links) (PDF)
Electrical switches are ubiquitous. Performance requirement for a switch is stringent. The operating mechanism mostly decides the performance of an electromechanical switch. However, design of such mechanisms, which involve discontinuous motions, is not much addressed in literature. The present work proposes a systematic procedure to design and analyze toggle based switching mechanisms. The work defined the toggle phenomenon rigorously, and, based on the behaviour of the toggles, provided a classification scheme for the switch mechanisms. The existing switches fall in two major categories viz., single-toggle and double-toggle switches. The double toggle mechanism is more suitable for high power breaking as it can isolate the system’s behaviour from the operator’s behaviour. The kinematic and geometric attributes of the operating mechanism which affect the toggle sequence and timings have been identified. A systematic simulation based study has been performed to identify the influence of different kinematic and dynamic parameters on the functionality of a double toggle switching mechanism. The influence of the variable moment of inertia and mechanism singularities arising out of introduction of the four bar sub chain on the performance of the system have been studied in detail. It is observed that the performance of the double toggle systems is less susceptible, though not immune to the user behaviour; in extreme scenarios the switching performance could become erratic. The use of an additional spring in an existing system enhanced the system performance; but, connecting the main spring with the coupler link altered the system performance more dramatically. Thus it established that the influence of the kinematic configuration on the performance of a switching mechanism is more pronounced than the dynamic characteristics of a comparable system. For the ab initio design of double toggle switching mechanisms, necessary structural criteria for a mechanism to exhibit double toggle phenomenon have been identified and verified with various 2 d.o.f. systems. It is also established that any double toggle mechanism cannot be used directly as a switching mechanism; the link dimensions, link arrangements and the stopper locations have to be chosen properly. Towards that end, three necessary kinematic criteria for a switching mechanism are identified. A few mechanisms which satisfy all structural and kinematic criteria are identified; the switching and toggle behaviour of these mechanisms are examined through simulations using Pro/Mechanism. Finally, considering all the conditions a is constructed with consideration of mass and geometric shape of the links. Thus, it established that the proposed methodology can systematically generate novel, structurally distinct electrical switches.

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