CL wadhwa bits solutions (93-100)

Lesson 16 of 21 • 49 upvotes • 14:12mins

Anvesh Sameer

93. An alternator is delivering a balanced load at unity p.f. the phase angle between line voltage and line current is: (a) 90° (b) 60° (c) 30° (d) 0°. 94. For the stable operation of interconnected system, the passive element that can be used a interconnecting element is: (a) Reactor (b) Resistor (c) Capacitor (d) Resistor and capacitor. 95. If two synchronous generators are connected, loss of synchronism will result in: (a) Stalling of generators (b) Wild fluctuations in current (c) Wild fluctuations in current and voltage (d) None of the above. 96. A generator is connected to a synchronous motor. From stability point of view it is preferable to have: (a) Generator neutral reactance grounded and motor neutral resistance grounded (b) Generator and motor neutrals resistance grounded (c) Generator and motor neutrals reactance grounded (d) Generator neutral resistance and motor neutral reactance grounded. 97. A 50 Hz, four-pole turboalternator rated at 20 MVA, 13.2 kV has an inertia constant H = 4 kW sec/kVA. The K.E. stored in the rotor at synchronous speed is: (a) 80 kilojoules (b) 80 megajoules (c) 40 megajoules (d) 20 megajoules. 98. The breakdown strength of air at STP is 21 kV/cm. Its breakdown strength at 30°C and 72 cm of Hg will be: (a) 21.25 kV/cm (b) 20.2 kV/cm (c) 23 kV (d) 19.5 kV/cm.   
 99. Corona loss is less when the shape of the conductor is: (a) Circular (b) Flat (c) Oval (d) Independent of shape. 100. Corona loss increases with: (a) Increase in supply frequency and conductor size (b) Increase in supply frequency but reduction in conductor size (c) Decrease in supply frequency and conductor size (d) Decrease in supply frequency but increase in conductor size.