Falkirk Wheel Drive Chamber Visit
With three colleagues I was very fortunate to be part of a technical tour of the wheel, organised by the Institution of Electrical Engineers, South East Scotland Retired Members Section.
Our tour was ably led by Mr Robert Jackson, senior engineer for the Wheel, who started with a brief outline of the operation (Doors and Seals) and the Falkirk Wheel Experience.
He continued by explaining that the plant to operate the wheel is in the rooms located in the final pillar of the aqueduct, shown left, adjacent to the wheel itself (to the right, just out of shot). This is the north end of aqueduct, at the south end of the wheel.
The area is entered from the door shown in the base of the structure, which is under the end of the aqueduct, and
consists of 7 chambers connected by marine type ladders. Note also the entrance
half way up the tower, with jib. This was used to install the plant and will be
The equipment is all located in the lower 4 rooms, the upper rooms are just part of the structure to hold up the end of the canal and house the mechanism for the aqueduct end door. The graphic on the right shows the rooms as they are used.
Note also the rooms are all rectangular, cast from concrete, with the outer curved appearance being achieved by the addition of external cladding.
We will start our journey at the bottom, entering the door shown
above at ground level and work our way up the tower through the four rooms marked on the
diagram, to the room with the jib, the Drive Chamber.
Ground Floor: 11KV Electricity Sub-station Room
The ground floor is occupied by the apparatus for the main incoming power for the Wheel, the standard transformer is located behind the mesh in the picture on the left. When the wheel was flooded by vandals in April 2002 this room was filled to within 3 inches of the 11KV bus-bars.
The picture shows the cramped marine-style ladders used to get
between the rooms, in this case taking us up to the first floor.
1st Floor: Standby Generator and Switchgear
Normally very quiet, however earplugs were available from a dispenser on the wall!
The set on the right (located in the NW corner of the room)
provides power in the event of mains failure to the Wheel and all associated
On the south wall fairly standard switchgear controls the supply
of power from the mains and standby generator.
2nd Floor: Hydraulic Room and Switchgear
Looking to the NW of this room, the hydraulic fluid is supplied from the pair of pumps shown right to the Drive Chamber located immediately above. It is supplied through electrically heated pipes (to prevent freezing in cold weather), the thick black pipes with yellow labels.
There have been no over-heating problems with this plant because of the wheels period of the rotation - the system never runs for more than 5 to 7 minutes at a time under normal operating conditions.
(picture by Tony Cowlin)
A slightly more exotic control panel in this room, again located on the south wall, which starts to address some of the unique problems associated with a rotating boat lift.
However looking north...
(picture by Allan Rhynas)
A door from this room faces directly onto the wheel, from here the planetary gears on the wheel can be viewed directly.
What you can see is the small gear at the bottom, and the large gear fixed around the central axle of the wheel at the top.
(picture by Peter McCulloch)
This exterior shot by Tony Cowlin tries to set the detailed picture in context.
In it the fixed gear around the central axle is left with the smaller gear to it's right.
This view looking out of the door to the west clearly shows the door frame on the left, the wheel on the right, with the fixed gear surrounding the central axle.
Below the lower basin and the "beak" of the wheel are seen.
(picture by Peter McCulloch)
A close up of the planetary gears, don't put you fingers anywhere near this!
Come to think of it don't put any part of your body anywhere near this, the wheel was rotating whilst our tour continued!
More seriously note that the planetary gears are not as straight forward as you may think. The lower (small) gear in the shot actually consists of a ring of rollers, each one with it's own lubrication feed. This ensures that slack is taken up in the same way as happens in a standard bicycle chain.
one last set of stairs...
3rd Floor: Drive Chamber
Not some Victorian Gallery resplendent with machines, this is it. In some ways it mirrors the simple, functional beauty, with a hint of style, of the wheel's exterior. The drive is applied directly to the axle through 10 hydraulic motors/brakes shown left around the central axle of the Wheel.
To give an idea of scale, the black centre inside the motors, with the ladder leading up to it, is just under 2 metres in diameter.
Notice also the outer thin black ring. There are 110 black caps covering the adjustment points for the roller bearings the wheel axle rotates on. These can also be seen from the visitor centre on the other end of the axle.
The hydraulic fluid comes in from the lower left of the picture to a silver control box between the upper two hydraulic motors. Control from the Fairfields Control System is provided by the grey box immediately above the silver box. Four lines go out to each motor, the fluid flow and return, as well as a control valve flow and return.
There is a separate page that talks about exactly how much energy is used to turn the wheel.
(picture by Allan Rhynas)
You can see and walk right through the axle, the door you can see at the far end is the one that can be seen from outside, immediately above the lower basin entrance to the wheel caisson.
This is not as surprising as it may seem. The original concept design had a pedestrian walkway through a clear plastic central axle. Unfortunately the laws of physics meant that when the engineers turned the concept into reality the axle became a solid metal tube.
Note the four electrical traces running through the axle (top and bottom right in the picture), I don't know what these are.
(picture by Peter McCulloch)
A close up of one of the 10 hydraulic control devices. This is the lower one on the right side.
Top left are the 4 hydraulic control lines that feed the motor/brake at the right hand side. Working left there is a 100:1 gear system that reduces the rotation speed. The final drive from all the motors then is transmitted to the axle via a large "cog" similar to the
planetary gears discussed earlier.
This room also contains a jib and crane, the picture on the right shows the jib immediately above the wheel axle. This is the same jib as can be seen in the exterior shot left (from the top of this page).
Equipment can be raised to this level, and located in this chamber or dropped through large access hatches in the floors as far as the First Floor. This is how the Standby Generator and Hydraulic Pumps were installed, and potentially maintained or replaced. The 11KV transformer was installed directly from the ground level.
Note also at the top right of the picture the cage, containing the stairs, taking you to the upper floors, finally bringing you out at aqueduct level.
(pictures by Tony Cowlin (left) & Allan
When designing the Wheel one of the problems was what building and safety standards to use? Is it a lift, a building, a fairground attraction, a canal lock, or what?
This is not a unique problem. A number of modern innovative structures don't fit into the pigeon holes we have used in the past. For example the London Eye works mainly to the Fairground Standards, however it is a lot more complex than those standards were originally written to cope with.
British Waterways worked with all the regulatory groups involved to pick the best from all the standards
without compromising any one standard or safety. Primarily the standards for industrial
lifts are used, with additions from other standards.
Mr Jackson concluded his highly interesting tour in the Drive Chamber, the vote of thanks was given by Charles Mckinder the Chairman of the IEE South East Retired Members section. Thanks also go to Bert Arnott from the IEE for organising the event.
Story and Pictures James Gentles (unless otherwise credited)
2nd April 2003.
return to the Millennium Link Resource Main Page