PHEP 26 Flashcards
IN 1 TYPE OF AC ELECTRODYNAMICNANOMETER INSTRUMENT THE 2 FIELD COILS AND THE SINGLE ARMATURE COIL ARE SO CONNECTED THAT
ALL COILS ARE IN SERIES
WHEN A THERMOCOUPLE IN A THERMOCOUPLE AMMETER IS HEATED IT PRODUCES
DC WHICH IS INDICATED ON A DC METER
WHEN USING A CROSS COIL POWER FACTOR METER ON A 3-PHASE CIRCUIT THE INSTRUMENT INDICATION IS ACCURATE
ONLY IF THE LOAD IS BALANCED AND THE POWER FACTOR IS THE SAME FOR ALL PHASES
A POWER FACTOR METER MEASURES THE
RATIO OF TRUE POWEER TO APPARENT POWER
MOST WATTMETERS ARE A/AN
ELECTRODYNAMOMETR
THE D’ARSONVAL ELECTORMAGNETIC MOVEMENT
CAN BE CONVERTED TO READ AC BY USING A BRIDGE RECTIFIER UNIT IN THE COIL CIRCUIT
A COPPER-OXIDE RECTIFIER IS A DEVICE THAT
IS CLASSED AS A UNI-DIRECTIONAL CONDUCTOR
AC VOLTAGES IN THE HIGHER RANGES ARE USUALLY MEASURED WITH A
VOLTMETER AND POTENTIAL TRANSFORMER
THE RANGE OF AN AC AMMETER MAY BE EXTENDED BY USING A
CURRRENT TRANSFORMER
AC AMMETER ARE GENERALLY CALIBRATED TO READ ROOT MEAN SQUARE VALUES. THIS ALSO MEANS THAT THE AMMETER IS CALIBRATED TO READ
EFFECTIVE VALUES
IN THE ABSENCE OF A POWER FACTOR METER THE POWER FACTOR OF A CERTAIN ELECTRICAL LOAD MAY BE DETERMINED BY USING
A WATTMETER, A VOLTMETER, AND AN AMMETER
THE JUNCTION OF THE 2 DISSIMILAR METALS OF A THERMOCOUPLE PRODUCES A FLOW OF CURRENT WHEN THE JUNCTION IS
HEATED
WHICH ONE OF THE BELOW INSTRUMENT TYPES WOULD NOT UTILIZE THE EFFECT OF CURRENT TO MEASURE VOLTAGE
ELECTROSTATIC
THE METER MEASURING MECHANISM USED IN RECORDING INSTRUMENTS IS BASICALLY THE SAME AS THAT USED FOR THE CONVENTIONAL INDICATING INSTRUMENT EXCEPT IN THE AREA OF
INSTRUMENT DAMPING SETTING
THE CIRCUIT ARRANGEMENT OF MOST GROUND DETECTOR METERS SHOWS THE NEUTRAL POINT OF THE GROUND DETECTOR POTENTIAL TRANSFORMER PRIMARY WINDING TO BE
SOLIDLY GROUNDED
