Essential Gyrators and Equivalence Rules for 3-port Junction Structures

It is shown that a theorem on essential gyrators presented by Rosenberg (1) and used in (2) claims too much and that the internal structure ofthe multiport elements ofthe system must be studied in order to be able to decide whether a gyrator is essentially contained in the system or not. Bond graph terminology is used (3H6) an d a new theorem is formulated, which provides un algorithm to decide on the essentiality of a gyrator by immediate inspection of the bond graph. As a side-result of this approach some new methodsfor junction structure simplification can be formulated. The signtjicance of junction 3-ports for the concept of the essential gyrator is elaborated by providing equivalence rulesfor all kinds ofjunction 3-ports and introducing a unit essential junction 3-port (ES) and a unit non-essential junction 3-port (NES). Finally the hydraulic junction is treated as an example of a physical non-potential junction, i.e. a junction congruent with an ES.