DGVCL Exam Paper (11-12-2011)
A 3 phase, 6 pole induction motor operates on 440 V, 50 Hz, supply. If the actual speed of the motor is 960 rpm the slip will be
Starting method of 1 phase I.M. Split phase starting Shaded pole starting types of 1 phase I.M. Resistor split phase motor capacitor spit phase motor Resistor split phase motors have poor starting torque capacitor split phase motor, capacitor connect series with auxiliary winding make angle 90˚ result in optimum starting torque.
all day efficiency is ratio of energy output to the energy input taken over 24 hour period. design distribution transformer for max. efficiency occurring at the avarage output power. performance of distribution transformer represent by all day efficiency.
Skin Effect: tendency of the current to crowd near the conductor surface.
Skin effect is proportional to frequency, conductor diameter and permiability. Skin effect increases effective resistance of conductor. In DC, no skin effect.
EXAMIANS