DGVCL Exam Paper (11-12-2011) The positive and negative sequence impedance of a transmission line are Infinite Different Zero Equal Infinite Different Zero Equal ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Depends on nature of load Unity power factor Lagging power factor Leading power factor Depends on nature of load Unity power factor Lagging power factor Leading power factor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Over excitation : leading currentUnder excitation : lagging currentNormal excitation : current with unity PF (in phase current)
DGVCL Exam Paper (11-12-2011) Bulk power transmission over long HVDC lines are preferred on account of No harmonic problems Minimum line power losses Simple protection Low cost of HVDC terminals No harmonic problems Minimum line power losses Simple protection Low cost of HVDC terminals ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Due to skin effect 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 Uniform current flows through the conductor Current flows through the half cross section of 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 Uniform current flows through the conductor Current flows through the half cross section of the conductor 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) A 3 phase, 6 pole induction motor operates on 440 V, 50 Hz, supply. If the actual speed of the motor is 960 rpm the slip will be 6 % 0.4 % 4 % 5 % 6 % 0.4 % 4 % 5 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ns = 120f/PSlip=(Ns-Nr)/NsNs = 1000 and Nr = 960 from equation of slip, S = (1000-960)/1000S = 0.04 or 4%
DGVCL Exam Paper (11-12-2011) The effect of electric shock on the human body depends on Current Duration of contact Voltage All of these Current Duration of contact Voltage All of these ANSWER DOWNLOAD EXAMIANS APP
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