Technology Groups > Marine Sensors And Electronics > Activities

Many of the system failures and losses at sea occur due to susceptibility of the electronics to the harsh conditions and lack of hands-on training for the personnel involved.  Wastage of ship time & cost and missing of crucial weather window can add to the woes such as loss of the instruments and material. Hence it is required to understand the conditions under which the underwater systems function and design them accordingly. It will be advantageous to test these systems under simulated conditions similar to underwater situations. Also rapid prototyping and training in operation can reduce the learning and acclimatizing time for the personnel responsible for the system performance in the field.

The following facilities to cater the needs of different activities of NIOT are being set up.

EMI & EMC Pre compliance testing Leak detection of underwater pressure cases Shock & Vibration Humidity Communication Cables & connectors Temperature & Salinity

EMI/EMC Analyzer

Early evaluation of system design’s EMI performance is essential for a successful instrument or system development. Similarly all the systems should comply with the EMC requirement before their operations.  Most of the underwater systems have many subsystems integrated with one another and affected by one another through the noise either radiated or conducted.  It is necessary that all the subsystems should be tested for EMI and EMC individually and also after the integration. Hence, as first step towards the establishment of the underwater electronic support facility, an EMC/EMI analyzer with broad frequency range along with the current probe, data logger and necessary software was procured and commissioned and is shown in Fig:1.  EMI/EMC analysis of the noise generated by the thrusters of remotely operable vehicle ROSUB 6000 has been carried out using this facility.

Impedance Analyzer

MS&E is developing sensors for different marine applications. Impedance analyzer is used to measure the impedance, reactance, susceptannce, admittance and analysis of components and circuits and is shown in Fig:2.. When circuit performance requires more accurate characterization of a component, it is necessary to verify the stated values, or to evaluate component performance under operating conditions (usually different than the manufacturer’s test conditions).Frequency dependency is common to all components because of parasitic inductance, capacitance and resistance. Micro Controller is the heart of any modern hand held equipment. Most of the instruments proposed to be developed can be based on the Microcontroller as a core. The firmware and the expertise can cut the development time to a large extent. Hence micro controller programmer & Keil software has also been procured. All the pressure casings that house the underwater electronics need to be tested for micro-openings, porosities etc. This can be accomplished using a light tracer gas which is capable of infiltrating the smallest gap quickly i.e. Helium. The leak can be from outside to inside and vice versa.

Helium Leak Detector

Hence a helium leak detection facility with options such as Global Test , Helium spraying Test, Sniffing test are available and is shown in Fig:3.

Battery Condition Monitor

The condition of Valve Regulated Lead Acid (VRLA) cells cannot be determined by simple voltage measurements. An additional measurement is cell impedance. Irrespective of the remaining ampere-hour capacity of a cell, it becomes useless when the impedance rises to a point where the internal voltage drop is too high when on load. A battery pack is only as good as its weakest cell and often this is only located when the battery is put to use. By monitoring individual cell or block impedance periodically during life, failures can be predicted and battery failure can be averted. Megger make battery condition monitor has been purchased and used for the monitoring of battery bank. The instrument is shown in Fig:4.

Underwater component development

The objective is to develop specialized non-off-the-shelf components (in Indian markets) for underwater applications in association with industry. NIOT is currently in the process of developing and deploying submersibles and underwater vehicles such as Data Buoys, Deep Sea Mining Crawler, ROV for 6000 metres, ARGO Buoys etc. Components such as cables, connectors, transformers, slip rings, underwater cameras, Power converters form major part of these systems and play a critical roll in the success of the project. These components are not always available off-the-shelf even in the international market. Many a time procuring these equipment and getting them serviced, when required, dictate the project schedules and costs.

Mock up connector made of Aluminum for pressure test.

One end of the connector

The Connector with male and female assembly

Prototype Marine Bronze Fiber Optic Connector

M/s FCI OEN were identified as the industry partner for the development of fiber optic connector. The design experience of the OEN connectors and the experience of NIOT scientists in underwater design are used for the manufacturing of these connectors. A mockup connector with aluminum  was fabricated and tested up to 200 bar at NIOT laboratory. The various stages of a mock up connector developed are shown in Figures 5 to 7 respectively. The development of underwater motor was taken up in collaboration with M/s PSG industrial Institute, Coimbatore. The design of the 250 kW motor was completed and major vendors for the sub systems of the motor also were identified. The engineering drawing for the motor is shown in the picture 8.

250 kW underwater motor assembly drawing