MGVCL Exam Paper (30-07-2021 Shift 2) In a synchronous motor with field under excited, the power factor will be unity zero lagging leading unity zero lagging leading ANSWER EXPLANATION DOWNLOAD EXAMIANS APP For synchronous motor,Under excitation - Lagging power factorOver excitation - Leading power factorFor synchronous generatorUnder excitation - Leading power factorOver excitation - lagging power factor
MGVCL Exam Paper (30-07-2021 Shift 2) A three-phase, 12 kV, 50 Hz and 300 kW load is operating at 0.8 pf lag. If the pf is to be improved to unity, using star connected capacitor, the per phase value of the reactive VAR required is: 25 kVAR 75 kVAR 100 kVAR 50 kVAR 25 kVAR 75 kVAR 100 kVAR 50 kVAR ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The reactive VAR required = kW*(tanφ1 -tanφ2)Cosφ1 = 0.8φ1 = 36.87 deg.Cosφ2 = 0φ2 = 0 deg.kVAR required = kW*(tan(36.87) - tan(0))= 300*1000(0.75)= 225.00 kVARPer phase value = 225.00/3= 75 kVAR
MGVCL Exam Paper (30-07-2021 Shift 2) Consider the following statements associated with Buchholz's relays.Statement 1: Buchholz's relay is a current operated device.Statement 2 : Buchholz's relay is placed between the transformer tank and the conservator. Both Statement 1 and Statement 2 are TRUE Statement 1 is FALSE and Statement 2 is TRUE Both Statement 1 and Statement 2 are FALSE Statement 1 is TRUE and Statement 2 is FALSE Both Statement 1 and Statement 2 are TRUE Statement 1 is FALSE and Statement 2 is TRUE Both Statement 1 and Statement 2 are FALSE Statement 1 is TRUE and Statement 2 is FALSE ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Buchholz relay is gas operated relay.It will operate when internal fault occurs in transformer.It is placed between tank to main conservator.It has two contacts trip and alarm.Use of Buchholz relay in distribution transformer is not economical.
MGVCL Exam Paper (30-07-2021 Shift 2) The Great Barrier Reef is located in which country? Australia Canada Germany India Australia Canada Germany India ANSWER DOWNLOAD EXAMIANS APP
MGVCL Exam Paper (30-07-2021 Shift 2) In a short circuit test on circuit breaker, time to reach the peak re-striking voltage is 50 µs with the peak restriking voltage of 100 kV. Determine average RRRV (Rate of rise re-striking voltage)? 2 x 10⁶ kV/sec 3 x 10⁶ kV/sec 1 x 10⁶ kV/sec 4 x 10⁶ kV/sec 2 x 10⁶ kV/sec 3 x 10⁶ kV/sec 1 x 10⁶ kV/sec 4 x 10⁶ kV/sec ANSWER EXPLANATION DOWNLOAD EXAMIANS APP RRRV = Peak value of restriking voltage/time to reach the peak re-striking voltageRRRV = 100*1000/(50 μs)RRRV = 2*10⁶ kV/sec
MGVCL Exam Paper (30-07-2021 Shift 2) In the following question, one part of the sentence may have an error. Find out which part of the sentence has an error and select the option corresponding to it. If the sentence contains no error, Select "No error'' option. (Avoid punctuation errors).(A) The Manager, with / (B) all his employee, was / (C) fired from the company /(D) NO ERROR A D B C A D B C ANSWER DOWNLOAD EXAMIANS APP
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