The strength of a magnetic field is specified by the magnetic induction B or by the magnetic field strength H. A current I through a long, straight wire produces a magnetic field with strength H = I/2πr at a distance r from the wire. Given H = 1 A/m I = 10 A H = I/2πr 1 = 10/2πr r = 10/2π
While estimating the overhead lines, the first and last pole is always earth connected and after every 3rd electrical pole, the fourth pole is earthed. Therefore, the approximate number of required ground set = 4
In terms of slip, the actual speed of the motor (N) can be expressed as N = Ns(1 − s) At start, the motor is at rest and hence its speed N is zero. s = 1 ( start) This is the maximum value of slip s possible for the induction motor which occurs at start. While s = 0 gives us N = N. which is not possible for an induction motor. So slip of the induction motor cannot be zero under any circumstances. Practically motor operates in the slip range of 0.01 to 0.05 i.e. 1 % to 5 %. The slip corresponding to the full load speed of the motor is called full load slip.
EXAMIANS