Voltages might be a less confusing way of looking at this concept, but might be harder to remember. As shown below, the dot convention distinguishes between two cases, where the polarities of the top node are the same, and when they are different. There are two ways to write each case, and the equivalent ways of writing them are shown.
Researchers Submit Patent Application, "Isolation of Secondary Transformer Winding Current during Auxiliary Power Supply Generation", for Approval
Jul 11, 2013; By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that...