Arbiter Systems 1040C User Manual

3-5
figures 5 and 6. Calibration can be performed
using the connections in figure 6 and one of
the methods outlined above, and in
accordance with the transducer manufacturers
recommendations.
Power factor output is also commonly
available as an additional feature on single
and multi-phase watt transducers. In this
case, the transducer is connected in the same
manner as a conventional watt transducer
(refer to figures 5 and 6).
Typical applications of power factor
meters for single-phase systems involve
circuit connections which are similar, if not
identical to those employed by single phase
watt and var meters. In light of this,
representative circuit and calibration
connection diagrams for these meters are
shown in figures 5 and 6. When connected
per the calibration setup diagram, calibration
of single-phase power factor meters can be
performed using one of the methods given
above, and in accordance with the meter
manufacturer's recommendations. For more
detailed instructions on operating the 1040C
for calibration of power factor, refer to section
2.5.1 of the operation manual.
Volt-Amps and Volt-Amps Reactive
Volt-Amps is the product of the rms
voltage and the rms current in a circuit,
without regard to the phase angle between
them. Another term commonly used to
describe this parameter is apparent power. If
a separate rms ammeter and rms voltmeter
were used to measure the current and voltage,
respectively, and the two values were
multiplied together, the result would be the
apparent power. This is not an indication of
the amount of work that can be done,
however; if the phase angle is 90 degrees
(power factor is zero), the true power
available is zero.
Volt-amps reactive (SI unit=var) is the
same as volt-amps, but with the phase angle
between voltage and current factored in. Vars
are a measure of the amount of power
required by the reactive portion of a load, and
actually represents circulating current in the
circuit. Vars are calculated as the product of
the RMS voltage, the RMS current, and the
sine of the phase angle between the two. For
an illustration of the relationship between
phase angle and vars when using the 1040C,
refer to figure 12.
The 1040C has a provision for displaying
and modifying both volt-amps and vars;
successively pressing the "Power" key during
operation will first display watts, then vars,
then volt-amps. The user can continue
indefinitely to scroll through these three
choices.
Some points of interest regarding va and
var measurements:
It is important to note that unless there is a
phase angle of greater than zero between
voltage and current, the var value will be
zero. Also, since va and var indications
are sub-functions of the power mode,
adjustment of these values using direct
entry, the control knob, or the up/down
keys affects the value by changing only
the current, not the voltage or the phase
angle. The current can only be modified
to a point within the current range of the
1040C. If the necessary current exceeds
this range, the display will indicate "Entry
Error". Additionally, if the phase angle is
set to zero and the user attempts to enter
any var value other than zero, "Entry
Error" will be indicated. This is because
under these conditions, no value of
voltage or current will produce anything
other than zero vars.
Typical applications of va and var meters
or transducers for single-phase systems

Arbiter Systems 1040C Specifications

General

Brand	Arbiter Systems
Model	1040C
Category	Test Equipment
Language	English