The Water Wheel - Welsh Slate Museum, Llanberis, Gwynedd, North Wales, UK
Posted by: 
Dragontree
N 53° 07.220 W 004° 06.926
30U E 425352 N 5886237
This is the largest working water wheel in the United Kingdom.
Waymark Code: WM6Q5M
Location: North Wales, United Kingdom
Date Posted: 07/06/2009
Views: 9
Originally this large water wheel was used to supply energy to all the Gilfach Ddu workshops for the slate quarries. It was built in 1870 and continued to perform to its original purpose until 1925 when the smaller Pelton wheel came into use. Measuring 15.4 metres in diameter this remains the largest water wheel in mainland Britain to this day and is now used to continuously demonstrate the machinery on display in the Welsh Slate Museum.
Powered by the Ceunant waterfall which lies above Llanberis, the water wheel is fed through cast iron pipes. Then the water rises to the tank above the wheel (because the source is higher than the level of the tank). To generate power the propulsion comes from the rim of the wheel and not the axle whose spokes just hold the wheel together as in a normal wheel mechanism. From the wheel many cogs and pinion wheels takes the energy produced from the buckets on the wheel along the line shafting and on to all the workshops on site.
The wheel has 140 buckets and starts to turn as soon as one of these fills due to its fine tuning.
In 1925 the wheel had become badly worn and caused all the work to come to a stop everytime it broke down. Therefore a Pelton wheel was inserted on a branch of the main pipeline, in the corner under the larger wheel. This wheel was much smaller but more efficient than the large wheel as it was powered by kinetic energy (from water rushing through a pipe which gradually got narrower) rather than water falling from a great height, as in the case of the water wheel. This Pelton wheel has only been known to fail once, during the hard winter of 1947, when the water froze in the pipes from the Ceunant waterfall.
The energy created by the water wheel is carried to the various workshops by means of line shafting. The lines of this shafting system were effectively the workshops' arteries, the means by which lathes turned and hammers pounded, and saws and drills moved back and forth. They carried the power from the wheel to every part of the workshops, bringing life to machines that would otherwise lie still.
Local engineers fashioned the wheel to the magnificent designwork we see today and which still survives 150 years later. It was restored in 2000 thanks to a grant from the Heritage Lottery Fund.
On permanent display in the museum visitors are encouraged to see the wheel up close by climbing the stairs or using the lift.
Visit Instructions:
Please give the date of your visit and a brief description of your experience and any additional information you may have about the waterwheel, its current condition, etc. We would very much like at least one original photo from your visit, but it is not absolutely necessary.