DGVCL Exam Paper (11-12-2011) The circuit breaker generally used in railway traction is Air break CB Bulk Oil CB Vacuum CB Minimum Oil CB Air break CB Bulk Oil CB Vacuum CB Minimum Oil CB ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The positive and negative sequence impedance of a transmission line are Infinite Different Equal Zero Infinite Different Equal Zero ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) It is difficult interrupt a capacitive current because Stored energy in the capacitor is very high It has a leading power factor The restriking voltage can be high Current magnitude is very small Stored energy in the capacitor is very high It has a leading power factor The restriking voltage can be high Current magnitude is very small ANSWER DOWNLOAD EXAMIANS APP
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) In a power plant, a reserve generating capacity which is not in service but is in operation is known as Firm power Spinning reserve Hot reserve Cold reserve Firm power Spinning reserve Hot reserve Cold reserve ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Due to skin effect 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 Current flows through the half cross section of the conductor Portion of the conductor near the surface carries less current and the core of the conductor carries more current 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 Current flows through the half cross section of the conductor 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.
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