| 摘要 |
In a ship or submarine grounding system for substantially eliminating the shaft-rate related alternating-field electromagnetic signature of the vessel, caused by the shaft-rate related modulation of the corrosion current , by maintaining the shaft at a fixed potential relative to the vessel's hull, in which the shaft-to-hull voltage is sensed and compared to a predetermined level and a current driver provides a current from the propeller shaft to reduce the continuous voltage between the shaft and hull, the output current is biased so as to also reduce the bearing modulated shaft current, between the shaft and the hull, which is caused by the residual voltage between the shaft and the hull. A balanced impedance amplifier senses the shaft-to-hull voltage and controls a current driver which provides current to the rotating shaft, a feedback loop biasing the current driver so as to substantially eliminate the effects of semiconductor bias voltage on the shaft potential, thus maintaining the shaft at the desired potential over the operating range of the output current, and thus substantially eliminating the modulation of the shaft current and substantially eliminating the resulting electromagneti c signature.
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