Signature management systems

Active Shaft Grounding system

The Active Shaft Grounding (ASG) offerings from EMS are fully integrated with the advanced ICCP systems and report voltage readings and current outputs back to the advanced ICCP controller. This then passes the data to the ship's communications.

An ASG system can be installed to ensure low resistance between the rotating shaft and the hull. The ASG system uses slip-ring sensors connected to the shaft to measure the potential difference between the shaft and hull. This senses the variation in current along the shaft and then uses a power supply to draw proportional current through a second slip-ring assembly. This system works as a current by-pass for the shaft bearings. Essentially, it acts as a ‘short’ between ground and hull with any readable resistance measuring lower than 0.001 ohms. Since the ASG system constantly adjusts, the resistance will stay the same throughout a complete revolution of the shaft.

This low level of resistance results in reduced alternating electric and CRM field signatures levels. These levels are undetectable by most sensors used for mines and torpedoes. They will meet most AEP and ACRM signature limit requirements for an extended time period, as compared to PSG, before maintenance is needed.

The ability to automatically adjust to minimize shaft resistance and modulation results in less potential for damage to the shaft bearings.

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ASG advantages:

  • Integrated with advanced ICCP system
  • Measures and transmits shaft voltage and ASG current output to the advanced ICCP controller
  • Advanced ICCP controller determines when maintenance or repair is need for ASG
  • Automatically adjusts for changes in shaft voltage by injecting current to produce a net "zero" shaft-to-hull voltage
  • Minimizes AEP and ACRM signatures and current through shaft bearings as the shaft rotates