TONG-TEST INSTRUMENT Russian patent published in 1998 - IPC

FIELD: electrical engineering. SUBSTANCE: tong-test instrument has current transformer to embrace conductor which carries current being measured. Current transformer winding is loaded by shunt. Auxiliary detector input is connected to shunt, and output is connected to comparator inputs. Other inputs of comparators are connected to respective dividers of reference voltage, and outputs of comparators are connected to logical circuit input. Logical circuit outputs are connected to control circuits of corresponding electronic switches and to digital indicator. In this case, some leads of each electronic switch are connected to inverting input of scaling amplifier, and other leads of electronic switches are connected to respective outputs of feedback divider of scaling amplifier the output of which is connected to scaling amplifier feedback divider and to rectifier unit. Noninverting input of scaling amplifier is connected to shunt and auxiliary detector. Digital indicator inputs are connected to out of analog-to-digital converter which is connected to reference-voltage source. Other output of reference-voltage source is connected to reference-voltage dividers which determine levels of comparator operation. Tong-test instrument allows improvement of high-speed action and operational characteristics. EFFECT: higher reliability in operation. 2 dwg