Asd Electrical Engineer

THE HONG KONG POLYTECHNIC UNIVERSITY DEPARTMENT OF ELECTRICAL ENGINEERING EE2011/2711 Applied electromagnetism Expt. No. 3 Field Plotting Using Conducting Paper Objectives: 1. 2. 3. dodge: To obtain the demesne pattern for a three-phase busbar understanding at selected time instants during the cycle. To familiarize with field plotting using conducting base and smooth-spoken paint. To obtain electrical parameters from field plots. Field-plotting kit (including sheets of carbon-loaded conducting paper, ash 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 Squargons It is evident that along an equipotential lift in that respect can be no electric field (since E = - dV/dx). It follows that a liquify line moldiness pass over an equipotential surface at right angles. Consider a l ower-ranking 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 with a1 is: d? ? D ? dA where D is the electric flux density of area a1.

(1) According to Gausss Law, the surface inviolate of the electric flux density must equal the measure charge enclosed: Q ? ? ? ? D ? dA (2) mental 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 permittivity of free space and ?r! is the relative permittivity of the dielectric. If we can borrow equipotentials and flux lines such that they form curving squares (squares with curved sides (see Fig. 2), so dy and dx are equal and the capacitance of each curved 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 in series(p) publication and...If you want to get a full essay, gear up it on our website: BestEssayCheap.com

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