Vigortronix 230v toroidal transformers single primary dual secondary vigortronix vtx 146 160 118 toroidal transformer open style 160va 230v ac primary winding 2x 0 18v ac secondary windings 150mm lead length ul csa tuv en60950en60065 compliant vigortronix vtx 146 160 118 toroidal transformer 230v single primary 160va 0 18v