For an open-delta secondary, there are two possible configurations for the primary side of the transformer bank. One is open-wye, with 120° between two phase-to-neutral primary connections. The other is open-delta, with 60° between two phase-to-phase-connected primary windings, that are typically symmetrical with the two secondary windings.
http://www.cooperpower.com/Library/pdf/R201902.pdf http://shop.ieee.org/ieeestore/Product.aspx?product_no=SS6924 [This message has been edited by Bjarney (edited 01-04-2005).]
