DGVCL Exam Paper (11-12-2011) The mutual inductance between two unity coupled coils of 9 H and 4 H is 13 H 2.2 H 6 H 36 H 13 H 2.2 H 6 H 36 H ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Due to skin effect Current flows through the half cross section of the conductor Uniform current flows through the conductor Portion of the conductor near the surface carries more current and the core of the conductor carries less current Portion of the conductor near the surface carries less current and the core of the conductor carries more current Current flows through the half cross section of the conductor Uniform current flows through the conductor Portion of the conductor near the surface carries more current and the core of the conductor carries less current Portion of the conductor near the surface carries less current and the core of the conductor carries more current ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Skin Effect:tendency of the current to crowd near the conductor surface.Skin effect is proportional to frequency, conductor diameter and permiability. Skin effect increases effective resistance of conductor.In DC, no skin effect.
DGVCL Exam Paper (11-12-2011) The efficiency of a transformer at full load, 0.8 p.f. lag is 90%. Its efficiency at full load, 0.8 p.f. lead will be 80 % More than 90% 90 % Less than 90% 80 % More than 90% 90 % Less than 90% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Efficiency= output power/input powerefficiency = (v*i*cosφ)/((v*i*cosφ)+(x² Pc)+(Pi)) x=fractional part of full load
DGVCL Exam Paper (11-12-2011) If the excitation of a synchronous generator fails, it acts as a Synchronous generator Synchronous motor Induction generator Induction motor Synchronous generator Synchronous motor Induction generator Induction motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP if excitation of synchronous generator fails, operate as induction motor
DGVCL Exam Paper (11-12-2011) A fuse is inserted in Neutral wire Phase wire Both phased and neutral wire Earth continuity conductor Neutral wire Phase wire Both phased and neutral wire Earth continuity conductor ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The bus bar zone faults are generally Phase to phase faults Single line to ground faults Three phase short ciruits Double line to ground faults Phase to phase faults Single line to ground faults Three phase short ciruits Double line to ground faults ANSWER DOWNLOAD EXAMIANS APP
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