Terex presents the AC 1000

Following the announcement in July 2006 that Terex would build a 1,000 tonne capacity telescopic boom wheeled mobile crane, the manufacturer in Zweibrücken, Germany, is getting ready to show its AC 1000 in the iron. Alex Dahm went to have a look at it.

Having braved freezing weather conditions of ice and snow during many hours of train journeys across continental Europe, your editor finally came face to face with the elusive Terex AC 1000 on a dim grey morning in Germany.

Elusive because the 1,000 tonne capacity wheeled mobile giant has been a couple of years longer than initially forecast in development. Let's apply an old saying here, though, "All good things come to those who wait".

Both on paper and in the iron, the AC 1000 makes a strong impression. It is about 50% stronger than the previous largest Terex wheeled telescopic mobile crane, the 700 tonne capacity AC 700. A primary area of application, perhaps as much as 50% of the work for the AC 1000, will be wind turbine erection and maintenance. With this in mind, an option is the SSL sideways superlift system for a capacity increase up to 200%.

The 2,900 tonne-metre range-topper is touted as the world's most powerful boom-on mobile crane. Another claim for the AC 1000 is that it has the most variable extension system for its main boom in its class.

It has two telescopic boom options - the HA50, which is a 50 m heavy duty boom or, with the addition of another unit of four telescopic sections inside the first, the HA100, a 100 m version. These four HA100 sections, with 245 tonne capacity integrated boom head, weigh 22 tonnes and can be transported on one standard EU truck. The 100 m boom is nine telescopic sections in total, including the base. A 363 tonne capacity heavy lift head is part of the 50 m boom as standard and needs no disassembly or exchange of parts, Terex said. The maximum boom and jib combination length on preliminary charts gives a hook height of 163.3 m.

Almost all customers will buy the AC 1000 with 100 m boom and full luffing jib, Terex said. Its most common boom and jib configuration, typically for wind turbine work, will be WIHI-VA-SSL with 34 m main boom + 16 m fixed lattice extension + 48 m offset lattice jib, giving a maximum load of 91.6 tonnes to a hub height of 90.6 m at a radius of 23 m, according to preliminary information. Even in the same boom and jib combination but with an extra 6 m in the offset jib (96.6 m hub height) capacity is 79.1 tonnes, or still enough to erect 80% of wind turbines that are being put up at the moment, Terex said.

An AC 1000 customer involved from an early stage was Ainscough Crane Hire, the UK's largest mobile crane rental company. Ainscough is due to get its two units in the first half of 2010. "We have had a lot of input with Terex Demag on the AC 1000. We gave them the target lifting capabilities, spelling out the sort of lifting capacities it was desirable to have to be able to manage some of the heavy lifts it coming up in the power related sector," explained Neil Partridge, Ainscough chief executive.

Mobility is a key feature. It is more flexible and you can bring less to the job site but still do the job, Terex said. Maximum counterweight is 228 tonnes and standard slabs that are also used on the Terex crawler crane range can be used. The heaviest component weight for transport is 26 tonnes. A three or four axle assist crane is used to help with assembly.

The AC 1000 can travel at 12 tonnes per axle, with the 50 m main boom, on 16.00 tyres with the Telma retarder, single line hook, without outriggers, superlift or hook block. In the UK, under STGO regulations at 16.5 tonnes per axle, it can travel on 16.00 tyres with the 100 m boom, Telma retarder, hook block and rear outriggers (front two removed).

"Ainscough was heavily involved in looking at what equipment the crane can carry within our STGO regulations so, what equipment the crane can carry on the way to its jobsite and what it can't, what has to go on the ballast wagons. There are a number of key areas that we have liaised with Terex Demag on to get to this final result," said Neil Partridge.

"The boom is on for a start, not off, which is the most fundamental thing. It can travel with two outriggers on and the other two have to be carried separately and the sideways superlift has to be carried separately. What it can't carry doesn't add any significant rig time anyway. That is one of the beauties of it," Partridge continued.

The nine axle carrier has 18 x 8 x 18 drive/steer configuration. On 16.00 R25 tyres it can move almost fully equipped on a jobsite without having to strip the machine down. Power is from a 480 kW Daimler diesel driving axles 2, 3, 5 and 6 via a ZF TC-Tronic-HD automated manual gearbox with torque converter and retarder. The speed dependent steering on axles 6 and 9 are a feature of the programmable active electronic steering system.

Outriggers are the star-type with only one axle between them, which gives more stability for the carrier frame, Terex said. Two spreads are possible - Max, which is 13.5 x 13.5 m and Mid, which is 9.9 x 9.6 m. Outriggers can be removed via quick connections for transport.

On the road with the 50 m boom, carrier length is 20.2 m without the rear outriggers, which add another 700 mm to the length when they are on. With the 50 m boom there is no front overhang as the tip sits behind the carrier cab. On 16.00 R25 tyres the AC 1000 is 3 m wide and 4 m tall.