TY - JOUR
AU - Brown, E B
AB - The polar ammeter is a moving coil instrument which can measure a.c. just as the permanent magnet moving coil instrument measures d.c. and in addition it gives the phase. A constant synchronous alternating flux is provided in its magnet system by a two pole magnet direct coupled to a two pole synchronous motor fed from the mans. The stator may be rotated about its axis and is graduated so that its angular position and thus the phase of the magnet flux may be observed on a fixed index.In measuring the magnitude and phase of a current passing through the moving coil the stator is turned until the instrument pointer indicates a maximum reading, which happens when the magnet flux is approximately in phase with the current, the instrument calibration is such that this reading is the r.m s. value of the current. The phase of the current can then be roughly determined by the stator position, but more exactly by turning the stator until the instrument pointer reads zero. The stator position is then exactly 90 from the true in-phase position. It is shown that the polar ammeter will give more correct readings of r.m.s. value than a rectifier instrument in measuring a current with distorted wave shape.
TI - The Polar Ammeter: A New Alternating Current Measuring Instrument
JO - Journal of Scientific Instruments
DO - 10.1088/0950-7671/24/8/301
DA - 1947-08-01
UR - https://www.deepdyve.com/lp/iop-publishing/the-polar-ammeter-a-new-alternating-current-measuring-instrument-Whr0aJAja0
SP - 197
VL - 24
IS - 8
DP - DeepDyve
ER -