DGVCL Exam Paper (11-12-2011) Which motor is used to start heavy loads? Series motor Shunt motor Differentially compounded motor Cumulatively compounded motor Series motor Shunt motor Differentially compounded motor Cumulatively compounded motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²starting torque of dc series motor is high
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 Spinning reserve Firm power Cold reserve Hot reserve Spinning reserve Firm power Cold reserve Hot reserve ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Lightning Magnetizing inrush current Switching over voltages Unbalanced protection Lightning Magnetizing inrush current Switching over voltages Unbalanced protection ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Initial inrush of magnetizing currents have high component of even and odd harmonics.2nd - 63%3rd -26.8%4th- 5.1%5th- 4.1%6th- 3.77th-2.4
DGVCL Exam Paper (11-12-2011) If the dielectric strength of the medium between the contacts builds up more rapidly than the restriking voltage the arc will Increase in size Decrease in size Extinguish Restrike Increase in size Decrease in size Extinguish Restrike ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The form factor in AC means the ration of R.M.S. value to peak value Peak value to average value R.M.S. value to average value Peak value to r.m.s value R.M.S. value to peak value Peak value to average value R.M.S. value to average value Peak value to r.m.s value ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In which of the following motors, the stator and rotor magnetic fields rotate at the same speed? Reluctance motor Synchronous motor Universal motor Induction motor Reluctance motor Synchronous motor Universal motor Induction motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In all machine stator and rotor magnetic field rotates (stationary with respect to each other) at synchronous speed with respect to stationary observer.
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