|
|
|
|
|
09/12/2010
(Read full story here or download PDF)
 Email to a friend
 Comment on this article
|
One of the world's most advanced survey vessels is now capable of positional accuracy down to ± one metre, thanks in part to bow and stern thrusters powered by variable speed drives.
 The Poseidon is the second vessel developed for seabed surveys by owner Neptune Survey Expedition, and has been equipped with a Norwegian Konsberg positioning system. That uses satellite navigation and a combination of the propellers, rudder, and variable speed and pitch thrusters to maintain its position.
Icelandic electrical contractor Rafeyri's technical manager David Hafsteinsson says that two Control Techniques Unidrive SP9432 drives, rated for heavy duty (450kW) motor output, control the bow and stern thrusters. The drives are controlled by a 4—20mA speed control signal from the Konsberg navigation PLC, he explains.
Each of the thrusters is tunnel-mounted beneath the ship, with motors direct-mounted on top of the screws. There is no gearbox, and the control system can decelerate the screws from full speed (1300rpm) in seconds, with pitch control similarly responsive.
Poseidon's current refit incorporates dual redundancy on most equipment, with the exception of the thrusters, because the drives each comprise four ac drive modules, providing inherent redundancy.
"The Unidrive SP solution was both competitive and, being modular gave a degree of redundancy," comments Hafsteinsson. "The issue of support was also important and, as the ship is to be surveying near Greenland and St Petersburg, the nearby Control Techniques Drive Centre in Reykjavik and Russia was another contributing factor," he adds.
|
|
| |
Author
Brian Tinham
|
| |
| |
|
| |
This material is protected by SOE copyright 2012.
See Terms and Conditions.
One-off usage is permitted but bulk copying is not.
For multiple copies contact the sales team.
|
| |
|
|
| |
|