PREVENTION OF ELECTROLYTIC CORROSION OF PROPELLER SHAFT SLEEVE FOR VESSEL

摘要

PURPOSE:To prevent titled electrolytic corrosion perfectly by connecting an amplifier to which a DC power source and a bias circuit having a specified continuous variation device to carbon brushes that contact a propeller shaft at two positions. CONSTITUTION:Carbon brushes 6, 6' are brought into contact with a propeller shaft 3 at two positions through a slip ring 4 near the propeller shaft sleeve 1, and these are connected to the positive terminal of an amplifier 8 and the negative terminal of a DC power source 9 respectively. The negative terminal of the amplifier 8 and positive terminal of the power source 9 are grounded to the hull. Current is applied between the sleeve and hull by the power source 9 having DC output corresponding to potential difference generated between the sleeve and hull and output of the power source 9 is adjusted automatically by voltage between the sleeve and hull. Accordingly, potential difference between the sleeve the hull can be maintained zero regardless of contact resistance of the brush. Further, by adding a bias circuit 10 to the amplifier 8 to give function to maintain the sleeve slightly negative potential than the hull, natural corrosion, besides electrolytic corrosion of the sleeve can be prevented.