DGVCL Exam Paper (11-12-2011) DC series motors are best suited for traction work because Torque and speed are inversely 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 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 inversely proportional to torque Torque and speed are inversely 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 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 inversely proportional to torque 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) The circuit breaker generally used in railway traction is Vacuum CB Air break CB Bulk Oil CB Minimum Oil CB Vacuum CB Air break CB Bulk Oil CB Minimum Oil CB 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 90 % Less than 90% 80 % More than 90% 90 % Less than 90% 80 % More 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) Which type of back up protection is widely used for the protection of transmission lines? Relay backup Remote backup Breaker backup Control backup Relay backup Remote backup Breaker backup Control backup ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Hysteresis in an instrument means The reliability of the instrument The change in the same reading when the input is first increased and then decreased The inaccuracy due to change in temperature The repeatability of the instrument The reliability of the instrument The change in the same reading when the input is first increased and then decreased The inaccuracy due to change in temperature The repeatability of the instrument 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 The length of the conductor Diameter of the conductor Spacing between the conductors Both spacing between the conductors and diameter of the conductor The length of the conductor Diameter of the conductor Spacing between the conductors ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Corona can be reduced by using large size of conductor, bundle conductor and hollow conductor.
EXAMIANS