The self-inductance is given as L = μN2A/I L ∝ N2 where N is the number of turns of the solenoid A is the area of each turn of the coil l is the length of the solenoid and μ is the permeability constant L1/L2 = N21/N22 0.5/0.5 = N21/N22 N1/N2 = 1
Galvanized steel conductors do not corrode, and possess high resistance. Hence such Wires are used in telecommunications circuits, earth wires, guard wire, stray wire, etc.
The shaded-pole motor is the original type of AC single-phase induction motor. Shaded pole-type single-phase induction motors are provided with shading rings on their poles which are the projected type of poles. The stator of such motors has projected poles like DC machines as shown in Fig. 5.7. The rotor is a squirrel cage type similar to that of split-phase-type motors. The poles are excited by giving a single-phase AC supply. A single-turn thick coil in the form of a ring called the shading ring is fitted on each side of every pole as shown. The portion of the poles where the shading ring is fitted is called the shaded portion, while the other portion is called the unshaded portion. The shaded pole motor has the lowest starting torque as compared to the all single-phase induction motors.
Penstock Penstock pipe is used to bring water from the dam to the hydraulic turbine. Penstock pipes are made up of steel or reinforced concrete. The turbine is installed at a lower level from the dam. The penstock is provided with a gate valve at the inlet to completely close the water supply. It has a control valve to control the water flow rate into the turbine.
EXAMIANS
