Laurel Electronics Laureate AC Power Factor Meter & AC Phase Angle Meter - Manual (Page 4)

LAUREL ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel 714-434-6131 • www.laurels.com 4
Application Examples
Optimizing Meter Inputs for Phase Angle & Power Factor Measurement
Phase angle and power factor measurement
with the Laureate™ Phase Angle & Power Factor
Meter require that two signals of identical periods
be applied to Channels A and B. For best accu-
racy, both signals should have the same ampli-
tude, the signal amplitude should be larger than
1V, and the trigger level should be minimized by
selecting the ±12 mV jumper position.
The meter times zero crossings to 0.1 µs resolu-
tion over a user-selectable gate time from 10 ms
to 199.99 s. By selecting the minimum gate time
of 10 ms, the meter update rate will be approxi-
mately 20/s for 50/60 Hz AC line frequency.
Improved accuracy will be obtained by making the
gate time long enough so that multiple cycles are
averaged.
Both signals applied to the meter should be
mutually isolated by transformer coupling, so that
they can then share the same ground in the
meter. The current signal is typically obtained
from a current transformer (CT). This should
ideally be a CT with a voltage output or a current
output in the mA range, which can then be
converted to a voltage higher than 1V across an
external dropping resistor without excessive heat
generation.
Using Laureate Meters and Counters to Synchronize Motor Generators
Synchronization of two motor generators
requires that the two frequencies be identical, that
the lines be in phase, and that the line voltages be
close to each other. In this illustration, a single
Laureate dual channel counter measures both
frequencies to six-figure accuracy in a few line cycles. Another Laureate dual channel counter
measures phase angle to 0.1° resolution. Two
Laureate AC RMS Voltmeters, which offer ranges
of 200.00 V and 600.0 V, are used to display the
two RMS voltages to 0.1% accuracy