The ratio of luminous flux leaving the surface (Reflected Light) to the luminous flux incident on it (Incident Light) is known as the reflection factor. Reflection Factor = Reflected light/Incident light The value of the Reflection factor is always less than 1.
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.
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.
EXAMIANS
