ment Р61._____ are used to reduce the sparking which occurs as the current collecting brushes move across the insulated segments РA.Windings РB.Field coils РC.Isolators РD.Interpoles Р62.The piston rings exert a varying pressure on the liner walls under conditions involving_____ . РA.constant speed РB.good lubrication РC.reversal of direction of motion РD.slowly changing speed Р63.If a ship is to be laid up for an indefinite period无限期, the saltwater side of the main condenser should be_____ РA.left filled with saltwater with the sea valves closed РB.drained and dried out after closing the sea valves РC.left filled with saltwater with the sea valves open РD.drained an refilled with saltwater after closing the sea valves Р64.Saltwater is typically provided to a refrigeration system to_____ .
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