Pelton Turbine

Pelton Turbine

Introduction

• The Pelton turbine is an impulse turbine which operate under a high head of running water and requires comparatively less quantity of water. 
• The water is conveyed from a reservoir in the mountains to the turbine in the power house through a long pipe called penstock.
• A nozzle is fitted at the end of the penstock through which water comes out in the form of a free and compact jet.
• The water jet having the velocity is made to impinge on the buckets fixed round the circumference of a wheel mounted on a shaft.
• The impact of the water on the surface of the bucket produces a force which causes the wheel to rotate,thus supplying a torque or mechanical power on the shaft.

Main components of Pelton Turbine

1. Guide Mechanism

• This mechanism controls the quantity of water passing through the nozzle and striking the buckets. 
• It maintain the speed of the turbine constant even head varies.
• it mainly consists of a deflector and a spear operated by a governor.

2. Buckets and Runner

• Each bucket is divided into two parts by a splitter giving the shape of a double hemispherical cup. 
• The buckets are bolted to the circumference of a round disc forming the runner of the Pelton Turbine.

3. Casing

• It is necessary to prevent splashing of water and to lead the water to the tail race and also as a safeguard against accidents.
• It has no hydraulic function to perform.

4. Hydraulic Brake

• It consists of water of a small nozzle  fitted in such a way that on being opened, it directs a jet of water on the back of the buckets to bring the revolving runner quickly to rest. The single jet pelton turbine shown in figure.