Les Hunt visited one of Manchester's newest landmarks, the elegant Urbis
exhibition building, to take a closer look at a novel lift installation
packed with unusual features
Directly opposite Victoria rail station in the heart of Manchester, and
surrounded by landmarks proclaiming the city's prosperous heritage, is a
rather striking glass-clad building, which has already gained the
sobriquet, 'Ski Slope', thanks to its bold, wedge-like shape. This is the
Urbis Building, a £30m development within Manchester's Millennium Quarter
that celebrates urban living on four staggered, mezzanine exhibition
levels, each reached by a novel funicular-style lift, whose track follows
the building's sloping profile. But unlike most lifts, which tend to get
hidden away in shafts, this one - including most of its working parts -
is an integral part of the building design and opened up for all to gaze
upon!
Main contractor on the Urbis construction, Laing, invited Doncaster based
firm, WGH International to join the bidding for the lift contract
following a similar project they had jointly worked on at the York
Railway Museum. With a history of building special rail track systems for
the mining industry, and currently the UK's only homespun constructor of
modern fairground rides, WGH won the Urbis lift contract and set about
fabricating the main structural elements early in 2000.
The entire lift support structure, comprising four 50m high, 250mm
diameter tubular support columns and a 42.4m long, 32o inclined track,
was transported to site in sections and lifted into place in the latter
part of 2000. The glass and stainless steel lift car, a joint
construction project involving principal companies, Rightform UK and H H
Martyn, was ready for installation late in 2001. Meanwhile, the Daventry
based lift control specialist, Digital Lift Controls (DLC), was already
several months down the line with the detailed lift drive and control
specification.
Architects, Ian Simpson conceived the lift as being part of the Urbis
exhibition experience. Rather than simply getting visitors to and from
floors as quickly as possible, the lift moves them sedately through the
exhibition levels, which are visible from the car's glass panels.
Consequently, smooth operation - particularly during acceleration and
deceleration - was deemed essential. And with most of the working parts
visible to, and well within hearing range of the public (the 37kW motor,
its gearbox and associated brake assembly, for example, are entirely
exposed but for a single safety glass panel), the installation had not
only to look good but be as quiet as possible! Moreover, with the motor
at the top of the lift installation separated by at least 50m from the
drives and lift logic panel located in a small room below floor level at
the foot of the track, the visual impact of the cabling also had to be
minimised.
Energy efficiency
While the Urbis lift is counter-weighted, it is some 1.5 tonnes out of
balance. On descent, energy that would otherwise have been dissipated as
the use of two four-quadrant regenerative drives supplied by Vacon UK. In
this unusual lift drive configuration, one drive connects to the supply
via an LCL filter, while the second is connected to the motor in the
conventional way, with both drives sharing a common dc bus. For DLC's
managing director, Yan Phoenix this was new territory, so in order to
familiarise him with the technique, Vacon invited Mr Phoenix to Stockholm
to view an existing lift installation based on Vacon regenerative drives.
The harmonic performance of these drives (in Urbis' case, Vacon CXI
series units) is also impressive. The specification called for a maximum
4% total harmonic distortion, whereas the measured value for the Urbis
installation is nearer 1.8%. The motor's noise emission levels, too, are
comfortably low at 46dBA, due in large part to the drive's rel