Pelton Turbine

Pelton turbine or Pelton wheel is an impulse turbine, unlike the Reaction Turbines of Francis and Kaplan. The main difference between a reaction and an impulse turbine is whether pressure is used. Reaction turbines use both pressure and kinetic energy to produce mechanical energy, whereas impulse turbines only use the kinetic energy of the water.

What stands out for the Pelton turbine is its distinctive spoon-shaped buckets capturing high momentum of water. We say high momentum because Pelton turbines are mostly used in conditions of high-heads, such as greater than 300 meters. Additionally, they operate with 85-90 % efficiency because of their design, allowing water’s kinetic energy to almost completely transform into mechanical energy.

Pelton turbine mainly consists of buckets, a runner, a drive shaft, and a water jet.

Buckets are shaped into two adjacent cups, splitting water. This superior shape of buckets allows nearly all the kinetic energy of water to be converted into torque just before discharging. The runner is the heart of the turbine, rotating constantly to produce mechanical energy with the drive shaft. The water jet is used as a nozzle to repel water to the buckets. Depending on the requirements, more than one water jet can be used.

The number of buckets ranges from 12 to 24, depending on the requirements. Generally, more buckets lead to smoother operation, as the force of water coming from the jet is more evenly distributed.

Pelton turbines require regular maintenance to perform optimally. The prior reason for maintenance is the debris, such as dirt and rocks, coming from the mountainous regions. Debris can enter the system and then damage the system. Sometimes, filtration systems are applied to minimize the number of debris.

To briefly summarize the Pelton turbines, water enters through the nozzle with high-velocity and strikes spoon-shaped buckets. As a result of the impact, the runner starts to rotate.

They are mostly used in hydropower plants located in mountainous regions and steep waterfalls. Their designs ensure minimal energy loss, making them highly effective. These features make them key components of hydroelectric power plants.

Runner of Pelton turbine

Basics demonstration of Pelton turbine

Eren Erden