Motor starters get shipbuilding under control

Edited by the Engineeringtalk editorial team Aug 7, 2003

More than 2000 Phoenix Contact rail-mounted reversing motor starters, with integrated Interbus facilities, are playing a key role in an innovative shipyard system.

More than 2000 Phoenix Contact rail-mounted reversing motor starters, with integrated Interbus facilities, are playing a key role in an innovative new fabrication system recently installed at one of the world's most modern shipyards.

Located in Papenberg, Germany, the shipyard is operated by Meyer, whose main business is the building of large cruise ships and luxury liners.

The new fabrication system is used in the manufacture of hull sections, which are traditionally formed from flat steel plates, with the aid of templates.

To replace this time-consuming and expensive method, Meyer uses a "hedgehog field" which is essentially an array of 2060 lifting elements arranged in the form of a grid covering a total area of 103 x 20m.

Each lifting element can be raised by up to 1m, with a precision of better than 1mm.

In use, one of the flat plates from which a hull section is to be formed is lowered onto the hedgehog field.

The individual lifting elements are then raised as necessary to produce the correct profile in the plate, using data supplied direct from a CAD system via an Ethernet link.

The plate deforms to the correct profile under its own weight, and frames are then welded to it so that this profile is maintained when it is lifted from the hedgehog field.

Although this fabrication technique is straightforward in principle, devising an economical control system presented a considerable challenge.

The standard approach would have been to use an ordinary reversing starter for each of the lifting elements, and to use parallel wiring to connect these starters to local programmable controllers with parallel wiring.

With 2060 lifting elements, however, the space required for the starters and the amount of wiring involved would have been prohibitive.

Instead, Meyer's engineers decided to use IB IL 400 ELR modules from the Phoenix Contact Inline range.

Each of these compact rail-mounting modules is, in effect, a solid-state reversing starter, with full motor protection facilities and a built-in Interbus interface.

Better still, the modules are designed to plug together, as far as possible, thereby greatly reducing the amount of wiring needed.

As an additional bonus, the modules also provide comprehensive real-time data about motor current and other operational parameters, available via the Interbus link.

This makes it possible for the control system to closely monitor the operation of each individual lifting element, without the need for additional equipment and wiring.

Providing control for the lifting element motors was, however, only part of the challenge.

The hedgehog field also incorporates 6180 sensors and other field devices which produce digital inputs for the control system.

Once again, conventional wiring would have been costly and difficult to install.

Phoenix Contact field-mounting Inline stations, each with 128 digital inputs, provided the solution, and helped to minimise the wiring requirements.

Dipl Ing Dieter de Boer, project leader for Janssen, the company which ran the hedgehog field project for Meyer, said: "Not only did adopting Phoenix Contact Inline solutions save money, it also helped us to minimise the overall project period.

The time needed for wiring was, of course, greatly reduced, but commissioning was also made much easier, as the plug-and-play design of the Inline modules virtually eliminated wiring errors".

The hedgehog field system at the Meyer shipyard is now fully operational, and is meeting or exceeding all performance targets.

In particular, the versatile monitoring and diagnostic facilities provided by Interbus, together with the inherent high reliability of the system, are ensuring that plant availability is maximised.