Vigortronix 230v toroidal transformers single primary dual secondary vigortronix vtx 146 1000 150 toroidal transformer open style 1000va 230v ac primary winding 2x 0 50v ac secondary windings 150mm lead length ul csa tuv en60950en60065 compliant vigortronix vtx 146 1000 150 1000va toroidal transformer 230v primary 2 x 50v