Alternator operated tachometer circuit

Claim 1

A CIRCUIT FOR USE IN OPERATING AN ELECTRICALLY POWERED METER FROM AN ENGINE DRIVEN ALTERNATOR HAVING THREE COILS CONNECTED TO A RECTIFIER BRIDGE FOR PROVIDING A DIRECT CURRENT POTENTIAL TO TWO TERMINALS CONNECTED TO OPPOSITE POLES OF A BATTERY FOR CHARGING SAID BATTERY WITH SAID BRIDGE INCLUDING TWO RECTIFIERS FOR EACH COIL SERIALLY CONNECTED ACROSS THE POLES OF SAID BATTERY AND ARRANGED TO EITHER PASS OR BLOCK CURRENT IN THE SAME DIRECTION WITH EACH TWO RECTIFIERS HAVING A TERMINAL CONNECTED INTERMEDIATE THE RESPECTIVE TWO RECTIFIERS TO A RESPECTIVE ONE OF THE COILS OF SAID ALTERNATOR WHEREBY THE POTENTIAL AT EACH INTERMEDIATE TERMINAL VARIES SUBSTANTIALLY AS A SQUARE WAVE ALTERNATING BETWEEN THE POTENTIAL AT SAID TWO TERMINALS IN RESPONSE TO POTENTIALS GENERATED ACROSS SAID COIL, THE CIRCUIT COMPRISING A SATURABLE TRANSFORMER HAVING A PRIMARY WITH ONE END OF SAID PRIMARY CONNECTED TO ONE OF SAID INTERMEDIATE TERMINALS, A FIRST RESISTOR CONNECTED BETWEEN THE OTHER END OF SAID PRIMARY AND EITHER ONE OF SAID TWO TERMINALS, A SECOND RESISTOR CONNECTED BETWEEN THE OTHER END OF SAID PRIMARY AND THE OPPOSITE OF EITHER OF SAID TWO TERMINALS, A TAP ON THE SECONDARY OF SAID TRANSFORMER CONNECTED TO ONE SIDE OF SAID METER, AND A PAIR OF UNIDIRECTIONAL CIRCUIT ELEMENTS RESPECTIVELY CONNECTED BETWEEN OPPOSITE ENDS OF THE SECONDARY OF SAID TRANSFORMER AND THE OTHER SIDE OF SAID METER WITH SAID ELEMENTS POLED TO PASS CURRENT IN THE SAME DIRECTION FROM SAID SECONDARY THROUGH SAID METER.