why we haven't any connection other than Delta or star in 3phase
Is it even theoretically possible to have another connection?
Extended delta is one connection.
Scott connection is another connection.
Open delta is another connection.
Zigzag is another connectiion
Double Y, double delta, open delta, & dual secondary w/ one Y & one delta phased for 12-phase rectification. There are creative combinations that people have come up with. Also, as stated above, a zig-zag is a useful connection. It allows the creation of an optimum ground point/node.
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