1,361 research outputs found
INFLUENCE OF ELECTRICAL PARAMETERS VARIATIONS ON STANDARD THREE-PHASE ASYNCHRONOUS MOTORS EFFICIENCY
No full textThis paper analyzes the sensitivity of the electromagnetical efficiency with respect to the electrical parameter variations for a series of standard three-phase asynchronous motors. At first, the electromagnetical efficiency of asynchronous motors is determined by referring to the electrical equivalent circuit of the motor; iron and copper losses are only considered. Then, the expression of the ratios between the p.u. variation of the efficiency and the p.u. variation of each electrical parameter are given either for fixed speeds or for fixed effective values of the stator phase current. Besides the p.u. variations of the efficiency are related to the contemporaneous p.u. variations of all electrical parameters by means of a simple relation
Il «Dique» del fiume Guadiana a Mérida: analisi costruttiva
No full textIn this article, we propose a study of the construction
process of the so-called “Dique” on the River Guadiana
in Mérida. The analysis of the construction of
this structure, which has traditionally been thought to
be a containment wall for the river, has allowed us to
pinpoint a series of aspects related to the architectural
characteristics of the monument: the stratigraphy of
the construction activities, the building techniques,
the study of the structural elements, the use of different
types of granite, the building phases, the technical
resources employed and, in general, the organisation
of the work
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