Asd Electrical Engineer

THE HONG KONG POLYTECHNIC UNIVERSITY DEPARTMENT OF ELECTRICAL ENGINEERING EE2011/2711 Applied electromagnetics Expt. No. 3 Field Plotting Using Conducting Paper Objectives: 1. 2. 3. whatchamacallit: To obtain the subject field pattern for a three-phase busbar organisation at selected time instants during the cycle. To familiarize with field plotting using conducting field and smooth-spoken paint. To obtain electrical parameters from field plots. Field-plotting kit (including sheets of carbon-loaded conducting paper, silver grey paint, connecting wires and sweeping pen) or PASCO Equipotential and Field Mapper; Variable dc power supply; Potential-divider (formed by connecting resistors on a breadboard); digital multimeter. Theory: Equipotentials and Curvilinear Squ bes It is evident that along an equipotential lift in that respect can be no electric field (since E = - dV/dx). It follows that a aggregate line moldiness run into an equipotential surface at right angl es. Consider a modest divisor of an electric field as shown in Fig. 1, where a1 and a2 are dickens equipotential surfaces, X1, X2, X3 and X4 are four electric flux lines. x1 x2 dy d? a2 a1 V V + dV Figure 1 X dx x4 x3 dz d? 1 The get flux passing by a1 is: d? ? D ? dA where D is the electric flux density of area a1.

(1) According to Gausss Law, the surface entire of the electric flux density must equal the innate charge enclosed: Q ? ? ? ? D ? dA (2) mental great power C ? dQ D ? dzdy D ? dz ? dy dy dy ? ? ? ? 0? r dz ? ? ?dz ? dV dV E ? dx dx dx (3) where ?0 = 8.85 ? 10-12 F/m is the pe rmittivity of free space and ?r is the relat! ive permittivity of the dielectric. If we can key equipotentials and flux lines such that they form curving squares (squares with curved sides (see Fig. 2), then dy and dx are equal and the capacitance of each curvilineal square (or cell) will be ?dz. In the system shown in Fig. 2, the dielectric may be considered to be made up of a large number of such cells in consequent publication and...If you want to get a full essay, ordinate it on our website: BestEssayCheap.com

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