Miniature linear drive from Sprint Electric provides motor control for sub-sea inspection device

The Nautilus scanner is a diver-deployed automated ultrasonic system that can operate in depths of up to 250 metres. The Nautilus scanner is designed to adapt to an in-situ mineral or gas pipe junction, or an existing pipe to monitor the quality of a new weld, or the condition of an existing pipe. These can be on land, shipboard or sub-sea. The sub-sea applications present the most demanding technical conditions.

Sonomatic has developed technology to overcome the difficult task of adding a new pipe junction (hot tap) to oil and gas pipelines on the sea bed.

A habitat is constructed around the hot tap site, approximately the size of a transportation container. The habitat is filled with a mixture of helium and oxygen to allow the divers to enter and work in a dry environment. The divers can work up to 150 metres under water, so providing these habitats is a major achievement itself.

With the Nautilus scanner fitted to the hot tap, Sonomatic technicians carry out inspection and analysis using Sonomatic's Microplus Digital Imaging System. Data is sent from the Nautilus scanner to the technicians through a 250 metres long umbilical cable. The data allows accurate mapping and analysis of the condition of the new pipe junction's weld.

Sonomatic chose the Sprint Electric 200XLV linear drive to provide the low voltage DC control for the Nautilus axis motors. Typically one motor would drive the circumferential axis to track around the pipe; the other would drive the axial axis which moves the scanner head in and out whilst rotating around the pipe.

The 200XLV was chosen because of its low noise signature. The low level electrical signals produced by the scanner make them very susceptible to electrical interference, especially when the signal cables are alongside power cables in the umbilical cable bundle. The 200XLV reduces the need for heavy filtering of the drive and motor cables over conventional PWM devices.

Sprint Electric's 200XLV is a miniature, fast response DC motor speed controller typically used for driving brushed DC motors, gear-motors, low inductance printed motors and linear actuators rated up to 100W. It is ideal for low power applications such as robotic control and antenna or security camera drives that rely on an unregulated DC or battery supply up to 48V. Offering high bandwidth and a superbly linear, noise free output, the 200XLV is ideal for control of linear actuators. Despite measuring just 40 mm wide, 82 mm high and 50 mm deep, the 200XLV is a genuine four quadrant drive that can motor and brake in both directions of rotation to offer outstanding control of motor speed and torque.