Drive successes in Chinese port cranes



Michael Nakulski, Business development of AC and DC drives, Control techniques Ltd, Powys, UK


At a time when we are seeing the world’s biggest expansion in port capacity, where else, but in China, one British company, Control Techniques, is enjoying major successes in providing large AC variable speed drives for port cranes in several Chinese ports. The latest of these is a huge project for around 160 drives in Xiamen Haicang Port in Fujian Province in the south of the country.

The port is now owned by Hutchisons Ports Holding (Hong Kong), the world’s largest port operator, who is acquiring many of China’s busiest ports. Xiamen is ranked number seven in China with a throughput of 3.34m TEU in 2005, an increase of 16.4 per cent on the previous year.

Control Techniques, part of Emerson Industrial Automation, with a well-established Drive Centre in Shanghai and a further Applications Centre in Beijing, has been working closely with a number of the major port crane OEMs in China.

These include ZPMC in Shanghai, the world’s leader in AC cranes, SPMP in Shanghai, Changzhou GT, GangDi in Wuhan and NOELL in Zhangzhou, proving AC drives for both new cranes and retrofits and DC drives primarily for retrofits in ship-to-shore (STS) and rubber-tire-gantry (RTG) port cranes.

“Our business in China started mainly with DC retrofits,” says Control Techniques’ Crane and Hoist Business Development Manager, Michael Nakulski. “Over the last  few years, we’ve supplied many DC drives for cranes from 10-40 tonnes in many Chinese ports. In these instances, generally the hoist and gantry shared one DC drive, the boom and trolley sharing another, with the Mentor II digital drives being fitted with a field current controller, a fieldbus adapter and running constant power hoisting control software for smooth anti-sway operation.

A typical example is the DC retrofit of an STS crane at Qingdao Port, with a 450-kW Mentor controlling the hoist and boom and a 125-kW Mentor for the trolley and boom. It was eight years ago that Control Techniques achieved its first success in the AC drives arena with an STC crane, with active front end, supplied by ZPMC for Shanghai Longwu Port. Using a common DC Bus supply and full sine-wave four-quadrature energy-saving operation, the configuration was for hoist and gantry to share one drive – in this instance a150-kW Unidrive – with a second 150-kW hoist motor drive synchronised in ‘digital lock’. A second size five Unidrive controlled the trolley (112-kW) and boom (45kW) motion.

ZPMC followed this up with an order for Control Techniques AC drives for a 1600 tonne float crane. Unidrives were supplied for the main hoist (2X480-kW), the 210 and 110-kW auxiliary hoists and the boom (2×480-kW). The crane operated with the main hoists in load sharing mode and communicated throughout using Profibus DP.

Control Techniques drives for port cranes

Control Techniques, is a global leader in the design and manufacturing of AC and DC variable speed drive technology with an installed base of over three million  drives worldwide. With experience in applying drives to cranes and hoists for more than 30 years, Control Techniques has developed this specialist technology to  maximise port crane productivity.

“Our design philosophy gives us major benefits in the port crane market,” explains Michael Nakulski. “Our Unidrive SP range has a modular design with standard  power modules thatdards. There is no variation in build, with thousands being made every year, so the field reliability is the best in the market. From the customer’s point of view, this means that modules are interchangeable.

Few spares need to be carried (keeping costs down) and, in the rare event of a failure, the crane can continue at a reduced capacity to complete the task in hand, until a convenient moment when the module can be interchanged in a matter of minutes, with no programming required. Should the module be a ‘master’, setting up of  parameters is as quick and easy as inserting a SmartCard. Everything is designed to minimise downtime and maximise port productivity.”

The Unidrive SP range is packed with features to meet the variation in crane design and operation needs. Wireless Ethernet gives connectivity to terminal  management systems, internal load measurement helps determine optimum hoisting and travelling speeds to maximise throughput and Secure Disable (to EN954-1 category 3 or 4) gives absolute safety when undertaking maintenance.

An RFI filter is a standard fitment and connectivity to all major fieldbus protocols such as Profbus and DeviceNet and 48-96 Vdc battery back-up facility to return allequipment to safe and secure positions in the event of a supply failure are options.

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