Tap changing furnace transformer

Claim 1

A THREE PHASE TAP CHANGING TRANSFORMER HAVING THREE PHASE WINDINGS PROVIDED WITH TAPS AND A MULTIPLE POSITION SWITCH AND A DELTA STAR SWITCH ASSOCIATED WITH EACH PHASE AND DRIVE MEANS FOR SAID SWITCHES, SAID MULTIPLE POSITION SWITCH HAVING A PLURALITY OF SPACED APART STATIONARY CONTACTS ARRANGED IN CIRCLE AND CONNECTED TO SAID TAPS AND A ROTARY CONTACT ADAPTED TO SEQUENTIALLY ENGAGE SAID STATIONARY CONTACTS, MEANS OPERATED BY SAID DRIVE MEANS FOR INTERMITTENTLY INDEXING SAID ROTARY CONTACTS OF ALL THREE MULTIPLE POSITION SWITCHES BETWEEN SAID STATIONARY CONTACTS, SAID DELTA STAR WHICH HAVING FIRST AND SECOND ARCUATE STATIONARY CONTACTS AND A MOVABLE CONTACT ELECTRICALLY CONNECTED TO SAID ROTARY CONTACT AND ADAPTED TO ALTERNATELY ENGAGE SAID FIRST AND SECOND CONTACTS AND TO BE WIPED ACROSS EACH SAID ARCUATE CONTACT IN A SERIES OF STEPS WHILE REMAINING IN CONTINUOUS ELECTRICAL ENGAGEMENT THEREWITH, SAID FIRST ARCUATE CONTACTS OF ALL OF SAID DELTA STAR SWITCHES BEING ELECTRICALLY COMMONED, SAID SECOND ARCUATE CONTACT OF EACH DELTA STAR SWITCH BEING CONNECTED TO SAID WINDING ASSOCIATED WITH ANOTHER PHASE, MEANS OPERATED BY SAID DRIVE MEANS FOR SIMULTANEOUSLY ACTUATING SAID MOVABLE CONTACTS OF ALL THREE DELTA STAR SWITCHES AND FOR INDEXING EACH SAID MOVABLE CONTRACT ONE STEP ACROSS ONE OF SAID ARCUATE CONTACTS EACH TIME SAID ROTARY CONTACTS ARE INDEXED TO A SUCCEEDING STATONARY CONTACT, WHEREBY SAID MOVABLE CONTACT ENGAGES A NEW POINT ON SAID ARCUATE CONTACT EACH TIME SAID MULTIPLE POSITION SWICH IS INDEXED AND EROSION OF SAID ARCUATE CONTACTS IS MINIMIZED, AND MEANS OPERATED BY SAID DRIVE MEANS FOR SIMULTANEOUSLY ACTUATING SAID MOVABLE CONTACTS OF ALL THREE DELTA STAR SWITCHES BETWEEN SAID FIRST AND SECOND ARCUATE CONTACTS ONCE FOR EACH REVOLUTION OF SAID ROTARY CONTACTS AND WHEN SAID INTERMITTENT INDEXING MEANS STEPS SAID ROTARY CONTACTS OF SAID MULTIPLE POSITION SWITCHES BETWEEN PREDETERMINED STATIONARY CONTACTS.