Multi-purpose electric meter for measuring current, voltage, phase angle, frequency and resistance

• US 3,205,439 A
• Filed: 06/17/1960
• Issued: 09/07/1965
• Est. Priority Date: 09/23/1959
• Status: Expired due to Term

• Current Assignee: Erich Grossner, Michael Sangl
• Original Assignee: Erich Grossner, Michael Sangl
• Inventors: MICHAEL SANGL, ERICH GROSSNER
• Application Number:
  US04/036,787
• Time in Patent Office: 1,908 Days
• US Class Current: 324/115
• CPC Class Codes: G01R 15/08 Circuits for altering the measuring range
• CPC Class Codes: G01R 15/12 Circuits for multi-testers , i.e. multimeters, e.g. for measuring voltage, current, or impedance at will

Claims

1. A UNIVERSAL MEASURING INSTRUMENT FOR MEASURING ACTIVE AND REACTIVE CURRENT, VOLTAGE, RESISTANCE, FREQUENCY AND A POWER FACTOR, COMPRISING A CURRENT METER, A BATTERY A PAIR OF RESISTANCE MEASURING TERMINALS, A VOLTAGE TRANSFORMER HAVING A SECONDARY AND MULTI-TERMINAL PRIMARY, A CURRENT TRANSFORMER HAVING A SECONDARY ANUD A MULTITERMINAL PRIMARY, A RING MODULATOR, A CENTER TAPPED SHUNT MEANS COUPLED TO THE OUTPUT OF SAID MODULATOR, A BRIDGE RECTIFIER, A GANGED MULTIPOSITION SELECTOR SWITCH FOR SELECTIVELY CONNECTING CIRCUITS TO MAKE SAID MEASUREMENTS, SAID SWITCH HAVING A FIRST POSITION FOR COUPLING THE SECONDARY OF SAID VOLTAGE TRANSFORMER TO THE INPUT OF SAID BRIDGE RECTIFIER AND SIMULTANEOUSLY COUPLING THE OUTPUT OF SAID RECTIFIER TO SAID CURRENT METER, MEANS FOR DECOUPLING THE CURRENT TRANSFORMER SECONDARY FROM SAID BRIDGE RECTIFIER, SO THAT SAID CURRENT METER MEASURES THE VOLTAGE APPLIED TO THE CORRESPONDING TERMINALS OF THE PRIMARY OF THE VOLTAGE TRANSFORMER, SAID SWITCH HAVING A SECOND POSITION FOR COUPLING THE SECONDARY OF SAID CURRENT TRANSFORMER TO THE INPUT OF SAID BRIDGE RECTIFIER AND SIMULTANEOUSLY COUPLING THE OUTPUT OF SAID RECTIFIER TO SAID CURRENT METER THROUGH SAID DECOUPLING MEANS, SO THAT SAID CURRENT METER MEASURES THE CURRENT APPLIED TO THE CORRESPONDING TERMINALS OF THE PRIMARY OF THE CURRENT TRANSFORMER, SAID SWITCH HAVING A THIRD POSITION FOR COUPLING THE SECONDARY OF SAID CURRENT TRANSFORMER TO THE INPUT OF SAID RING MODULATOR, FOR COUPLING THE OUTPUT OF SAID MODULATOR TO SAID CURRENT METER, AND FOR COUPLING THE SECONDARY TERMINAL OF SAID VOLTAGE TRANSFORMER TO THE INPUT OF SAID MODULATOR THE OTHER SECONDARY TERMINAL TO THE CENTER OF THE SAID SHUNT, VARIABLE RESISTANCE MEANS COUPLED TO SAID CURRENT METER FOR ADJUSTING SAID METER INDICATION TO FULL SCALE WHEN SAID SWITCH IS IN SAID THIRD POSITION SO THAT SAID CURRENT METER MEASURES THE COSINE OF THE ANGLE BETWEEN THE CURRENT APPLIED TO THE PRIMARY OF SAID CURRENT TRANSFORMER AND THE VOLTAGE APPLIED TO THE PRIMARY OF SAID VOLTAGE METER, SAID SWITCH HAVING A FOURTH POSITION FOR INTERCHANGING THE INPUT CONNECTION TO SAID CURRENT METER COUPLED TO SAID CIRCUITS IN SAID THIRD SWITCH POSITION, SAID SWITCH HAVING A FIFTH SWITCH POSITION FOR COUPLING THE SECONDARY OF SAID VOLTAGE TRANSFORMER TO SAID BRIDGE RECTIFIER THROUGH INDUCTANCE MEANS, FOR COUPLING THE OUTPUT OF SAID RECTIFIER TO SAID CURRENTG METER THROUGH SAID VARIABLE RESISTANCE MEANS WHEREBY THE INDICATION ON SAID METER IS INITIALLY ADJUSTED TO FULL SCALE BY SAID VARIABLE RESISTANCE MEANS WHEN SAID SELECTOR SWITCH IS IN THE FIRST POSITION SO THAT WHEN SAID SWITCH IS IN SAID FIFTH POSITION THE INDICATION OF SAID CURRENT METER IS RESPONSIVE TO THE FREQUECY OF THE VOLTAGE APPLIED TO THE PRIMARY OF SAID VOLTAGE TRANSFORMER, SAID SWITCH HAVING A SIXTH POSITION FOR COUPLING THE INPUT TO SAID CURRENT METER IN SERIES WITH SAID BATTERY AND SAID VARIABLE RESISTANCE MEANS TO SAID PAIR OF RESISTANCE TERMINALS MOMENTARY SWITCH MEANS FOR CLOSING SAID TERMINALS MOMENTARILY TOGETHER TO ALLOW SAID CURRENT METER TO BE SET TO A NULL INDICATION BY ADJUSTMENT OF SAID VARIABLE RESISTANCE MEANS, SO THAT THE INDICATION OF SAID CURRENT METER WILL BE RESPONSIVE TO THE MAGNITUDE OF THE RESISTANCE COUPLED TO SAID OPEN TERMINALS.