Water wheel benefits from finely tuned gearbox

Nicola Brittain

A new gearbox provides good alignment and reduces power loss.

The largest diameter electricity-generating waterwheel in Europe has adopted new technology from technology manufacturer Apex Dynamics.

The impressive new hydro project from family-owned self-drive plant hire company Buckland Newton Hire (BNH) saw Apex Dynamics UK supply the inline planetary gearbox used to control the waterwheel. It has provided the wheel with near-perfect alignment, high efficiency and minimal power loss through transmission to ensure as much electricity as possible is generated, according to the company.

Based near Dorchester, Dorset, the waterwheel is the largest electricity generating wheel in Europe at nine metres in diameter.

To achieve the required head for the project, BNH raised one of the lakes on the family farm by around 11 metres. The lake is supplied from a large spring and run-off rainwater from the valley slopes.

The galvanised steel waterwheel, which has 92 individual buckets carrying a total of six tonnes of water at a time, now delivers an average flow of approximately 150 litres per second 24/7 nearly all year round, supplying an average of 150 kWh per day. This contributes around one-third of the total electricity needed for the site - which includes more than 20 industrial units,.

The Apex Dynamics gearbox

An Apex Dynamics NB series linear 3 stage planetary gearbox is in line with the waterwheel shaft and connected to the generator via a pulley and belt system. The waterwheel rotates at 4.5 rpm and the Apex gearbox provides additional flexibility to fine tune the speed up to 450 rpm at the 48 mm gearbox output shaft. The high torque from the waterwheel is accommodated at the 140 mm diameter input shaft of the gearbox.

Getting the shaft size to match was very important to the project. Having incorporated a flexible grid coupler into the system design to accommodate any misalignment, this has proven unnecessary because the NB servo gearbox perfectly aligned with the input and output shafts but has been retained as a safety feature. The pulley and belt connection delivers the required 1,500 rpm to the generator.

In addition to plant hire, BNH also runs a number of related operations, including specialist groundworks projects.

The business had previously installed renewable energy - such as wind turbine, solar installations and hydro schemes and was inspired to install its own waterwheel to power its business operations, nearby houses and family farm. The company is now looking for new ways to repeat the success of its waterwheel project.




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