MGVCL Exam Paper (30-07-2021 Shift 2)
A three-phase 400 V, 6-pole, 50 Hz squirrel-cage induction motor is running at a slip of 5%. The speed of rotor with respect to stator magnetic field and speed of the stator magnetic field with respect to rotor magnetic field are
Slip, s = (Ns - Nr)/Ns Ns = 120f/P 0.05 = (1000 - Nr)/1000 Nr = 950 rpm Speed of rotor with respect to stator magnetic field = 950 - 1000 = -50 rpm
Speed of the stator magnetic field with respect to stator core = 0 Speed of the rotor magnetic field with respect to rotor = sNs Speed of the stator magnetic field with respect to rotor magnetic field = 0 Speed of the rotor magnetic field with respect to stator core = Ns
A term brown out means it is an intentional or unintentional drop in voltage in an electrical power supply system. Brown outs are long-term (hours-long) voltage sags caused by system overload. Deviations from the regular sinusoidal wave, both on the utility side and on the customer side, result in poor power quality.
EXAMIANS