Thanks to @tigger for suggesting this one - the small building housing the water turbine is not labelled on maps, so I would never have known about it otherwise.
It used to provide electricity for a nearby house and with half its roof missing looks like any one of thousands of derelict farm buildings scattered across Wales.
The only sign that there might be a turbine inside is the inlet pipe coming down from a weir on a nearby river.
No external since it was in a fairly busy and overlooked location when I first walked past - I came back later when it was dark.
Pictures are a mixture of phone and camera.
Circling the beast, the big wheel on the left is the main flow control on the inlet coming through the back wall.
Fflywheel, governor (in front) and generator.
A ring of connected shafts, bottom left, for moving control vanes inside the turbine.
The firm who made this one (Armfield) were well know for water turbines at one stage.
Derelict examples seem to be more common further south where they were based, but I came across a similar machine a while ago in a Cumbrian gunpowder works, https://www.28dayslater.co.uk/threads/lowwood-gunpowder-works-cumbria-dec-2019-jun-2020.123656/.
There was also an Armfield turbine, but of a different design, in Blackpool Mill in Pembrokeshire.
On the way across Wales I inspected another turbine location, also an anonymous box on maps, which supplies electricity to Palé Hall near Bala.
The old turbine in here (a Gilkes) has been retired and now sits alongside a new one which is humming busily away - it was just about possible to see them through the grilled windows but not to get a decent picture of either.
Since these old hydro setups may not always be labelled as such there could be more hiding in plain sight.
It used to provide electricity for a nearby house and with half its roof missing looks like any one of thousands of derelict farm buildings scattered across Wales.
The only sign that there might be a turbine inside is the inlet pipe coming down from a weir on a nearby river.
No external since it was in a fairly busy and overlooked location when I first walked past - I came back later when it was dark.
Pictures are a mixture of phone and camera.
Circling the beast, the big wheel on the left is the main flow control on the inlet coming through the back wall.
Fflywheel, governor (in front) and generator.
A ring of connected shafts, bottom left, for moving control vanes inside the turbine.
The firm who made this one (Armfield) were well know for water turbines at one stage.
Derelict examples seem to be more common further south where they were based, but I came across a similar machine a while ago in a Cumbrian gunpowder works, https://www.28dayslater.co.uk/threads/lowwood-gunpowder-works-cumbria-dec-2019-jun-2020.123656/.
There was also an Armfield turbine, but of a different design, in Blackpool Mill in Pembrokeshire.
On the way across Wales I inspected another turbine location, also an anonymous box on maps, which supplies electricity to Palé Hall near Bala.
The old turbine in here (a Gilkes) has been retired and now sits alongside a new one which is humming busily away - it was just about possible to see them through the grilled windows but not to get a decent picture of either.
Since these old hydro setups may not always be labelled as such there could be more hiding in plain sight.