Super hoists enable Intimate Mode at Etihad Stadium

Etihad Stadium, in Melbourne’s Docklands precinct, is one of Australia’s leading multi-purpose venues designed to cater for major sporting and entertainment events.

The stadium, with its fully retractable roof, is capable of seating close to 54,000 patrons. Other than AFL, it hosts many other major sporting codes, interspersed with a number of headline international entertainment acts. Around 90 sports and entertainment events are hosted on the arena each year.

The natural turf arena covers a total area of 19,000m2, and from fence to fence the arena dimensions are 169.5 meters from north to south and 140 meters from east to west.

For some events, the stadium’s management has seen the need to make the venue ‘smaller’ and more intimate, so a top level design and engineering solution was sought from Harris Movement Engineering (HME). This led to what Etihad Stadium now calls its ‘Intimate Mode’.

HME is a solutions provider in machine and automation design, including meeting various hoisting, rotation and translation challenges.

Previous major projects involving HME include responsibility for the concept design, detail design, manufacture and installation of the huge machinery to drive the rotating stage for the technically advanced audio-visual show at the Australia Pavilion at World Expo Shanghai in 2010.

Dolly good idea

For the Etihad Stadium project, the solution involved 180 meters of truss holding up 20 meters drops of fabric to form a wall.

HME's Super Stadium Hoist ensured that every lift line always operated in perfect unison.HME’s Super Stadium Hoist (pictured alongside) ensured that every lift line always operated in perfect unison.

According to HME’s automation engineer, Chris lland, the design of the truss/ curtain/ dolly idea was simple enough, but lifting them into the air presented a complicated challenge.

"A rigging solution was designed to solve the problem and ensure that the whole system could be deployed quickly with a minimal crew. This was achieved using a high speed and high capacity customised hoist, now called the HME EDH1500 Super Stadium Hoist, which ensured that every lift line always operated in perfect unison," he explained.

"We used three Mitsubishi FR-A741 7.5K drives in the project. They each run a 1.5 meter per second 1,500 kg SWL (Safe Working Load) six-line, 40 metre drift hoist. The hoists, which are wireless controlled, each lift a 60 metre long truss with a 20 metre tall curtain made of black wool and weighing around 1,200 kg.

"So in total that’s 180 metres by 20 metres, which amounts to 3.6 tonnes of curtain, making it what we believe is the biggest curtain in Australia.

HME chose the Mitsubishi FR-A741 7.5K drives because of the inbuilt regenerative braking system.HME chose the Mitsubishi FR-A741 7.5K drives (pictured alongside) mainly because of the inbuilt regenerative braking system and the FR-A700’s proven track record.

"Due to the environmental conditions, having a break resistor on the outside of the cabinet was not an option.

"By using the FR-A741, HME was able to keep all the components in a suitable IP rated enclosure," explained Iland.

Designed for unison lifting

IIand says the entire Intimate Mode Hoisting System is designed for unison lifting. Each segment can be lifted at a speed of 1.5m per second – so the entire load can be moved from ground to roof or vice versa in well under a minute.

"Each hoist manages 240 meters of SWR which is done as six lines of 40 meter drops to pick up each truss.

"Drums of the hoists are 300 mm in diameter and over two meters in length, and each hoist weighs in at over 800 kg. Dual brake discs and circuits act on the hoist drums to ensure safety is maintained at all times.

"The hoists were built to specifically ensure that all components are rated and protected for outdoor use, and each hoist is covered in painted panels to camouflage the system in the ceiling structure of the stadium."

Alex Prendergast at Mitsubishi distributor, Oceania Automation, says the FR-A741 compact frequency inverter delivers exceptional performance and is ideal for hoist and high-powered machines with torque that can be used for regenerative braking.

"The integrated power regeneration function of the FR-A741 makes it possible to use smaller and much less expensive drive systems, and enables simpler and more compact switchgear cabinet layouts. As a result, initial investment outlay and operating costs are kept low," Prendergast said.

"Drive motors usually account for most of the power used in mechanical engineering installations, but the FR-A741’s regenerative braking system makes it much more efficient than conventional drive systems, giving it the potential for significant energy savings.

"Also, the integrated AC reactor, plus no need for an external braking unit, means that a large amount of wiring is eliminated. These inverters need up to 60 percent less main circuit wiring and occupy up to 40 percent less space than conventional solutions, depending on the output capacity."

More versatility in staging events

Etihad Stadium CEO, Ian Collins, said it was felt the Intimate Mode concept would give the stadium more versatility in regards to the staging of some of its events.

This digitally enhanced image shows how Intimate Mode could look at Etihad Stadium.The digitally enhanced image alongside shows how Intimate Mode could look at Etihad Stadium.

"The venue has a proven track record of hosting large arena events for up to 70,000 patrons. The new Intimate Mode allows us to cater to a different market and provide an opportunity for events of any size," he said.

"The stadium has always had the capacity to do things differently due to our retractable roof, which allows events to go on without any interruption. We see Intimate Mode as another innovation that will allow Etihad Stadium to stand out from the crowd."

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