MGVCL Exam Paper (30-07-2021 Shift 1)
If a 415 V, 50 Hz, star-connected, three-phase squirrel-cage induction motor is operated from a 415 V, 70 Hz supply, the torque that the motor can now provide while drawing rated current from the supply
reduces
increases
remains the same
increases or reduces depending upon the rotor resistance
For small turbine starts generating power 12.6 kph (3.5 m/s) is the typical cut-in speed. At 36–54 kph (10–15 m/s) produces maximum generation power. At 90 kph (25 m/s) maximum, the turbine is stopped or braked.
Symmetrical breaking current: It is the rms value of a a.c component of the current in the pole at the instant of contact separation.
Asymmetrical breaking current: It is the rms value of the total current comprising the a.c and d.c components of the current in the pole at the instant of contact separation.
EXAMIANS