DGVCL Exam Paper (11-12-2011)
Which of the following correctly represents the sequence of operations of isolator, circiut breaker and earthing switch while opening a circuit?
Open circuit breaker-open isolator-close earthing switch
Close circuit breaker-close isolator - open earthing switch
Open isolator close circuit breaker-open earthing switch
Close earthing switch - open ciruit- breaker-open islotor
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.
In all machine stator and rotor magnetic field rotates (stationary with respect to each other) at synchronous speed with respect to stationary observer.
EXAMIANS