Transformer Design for Zero Phase Shift

A design method for obtaining minimum phase shift between output and input of a transformer is described. The method is applicable to precision reference transformers employed in analog computers and servo loops where minimum quadrature voltages are mandatory. A rigorous analysis of the equivalent circuit of the transformer demonstrates that the transformer can be treated as a combination lead and lag network to yield zero phase shift. This is done by making the ratio of primary resistance to primary shunt reactance equal to the quotient of total leakage reactance and load resistance. The procedure consists of l) designing for theoretical zero phase.