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 0.4 % 4 % 6 % 5 % 0.4 % 4 % 6 % 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) DC series motors are best suited for traction work because Its torque is proportional to the square of the armature current and speed is directional proporational to torque Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Torque and speed are inversely proportional to the square of the armature current Torque and speed are proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is directional proporational to torque Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Torque and speed are inversely proportional to the square of the armature current Torque and speed are proportional to the square of the armature current ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²N α 1/φN α 1/T
DGVCL Exam Paper (11-12-2011) Ybus used in power flow studies and Zbus used in short circuit studies Have no inter relation Are inverse of each other Are transpose of each other Are the same Have no inter relation Are inverse of each other Are transpose of each other Are the same ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The corona effect can be minimized by increasing Both spacing between the conductors and diameter of the conductor Diameter of the conductor Spacing between the conductors The length of the conductor Both spacing between the conductors and diameter of the conductor Diameter of the conductor Spacing between the conductors The length of the conductor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Corona can be reduced by using large size of conductor, bundle conductor and hollow conductor.
DGVCL Exam Paper (11-12-2011) Which of the following correctly represents the sequence of operations of isolator, circiut breaker and earthing switch while opening a circuit? Open circuit breaker-open isolator-close earthing switch Close circuit breaker-close isolator - open earthing switch Close earthing switch - open ciruit- breaker-open islotor Open isolator close circuit breaker-open earthing switch Open circuit breaker-open isolator-close earthing switch Close circuit breaker-close isolator - open earthing switch Close earthing switch - open ciruit- breaker-open islotor Open isolator close circuit breaker-open earthing switch ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) A fuse is inserted in Both phased and neutral wire Phase wire Earth continuity conductor Neutral wire Both phased and neutral wire Phase wire Earth continuity conductor Neutral wire ANSWER DOWNLOAD EXAMIANS APP
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