YOKOGAWA WT500, User Manual

Page: 315 / 360

14-14
IM 760201-01E
Item Specifications
Sample rates, window widths, and upper limits of harmonic analysis
Fundamental frequency Sample rate Window width Upper limit of harmonic analysis
10 Hz to 75 Hz f × 1024 1 50
75 Hz to 150 Hz f × 512 2 32
150 Hz to 300 Hz f × 256 4 16
300 Hz to 600 Hz f × 128 8 8
600 Hz to 1200 Hz f × 64 16 4
Accuracy, ±(reading error + measurement range error)
• When the line filter is off
Frequency Voltage and current Power
10 Hz ≤ f < 45 Hz 0.15% of r 0.35% of range 0.35% of r 0.5% of range
45 Hz ≤ f ≤ 440 Hz 0.15% of r 0.35% of range 0.25% of r 0.5% of range
440 Hz < f ≤ 1 kHz 0.2% of r 0.35% of range 0.4% of r 0.5% of range
1 kHz < f ≤ 2.5 kHz 0.8% of r 0.45% of range 1.4% of r 0.6% of range
2.5 kHz < f ≤ 5 kHz 3% of r 0.45% of range 5% of r 0.6% of range
• When the line filter is on (5.5 kHz)
Frequency Voltage and current Power
10 Hz ≤ f < 45 Hz 0.4% of r 0.35% of range 0.85% of r 0.5% of range
45 Hz ≤ f ≤ 440 Hz 0.75% of r 0.35% of range 1.5% of r 0.5% of range
440 Hz < f ≤ 1 kHz 1.2% of r 0.35% of range 2.4% of r 0.5% of range
1 kHz < f ≤ 2.5 kHz 5% of r 0.45% of range 10% of r 0.5% of range
The items listed below apply to all of the tables.
• When the crest factor is set to 3.
• When
λ
(the power factor) is 1.
• Power figures that exceed 440 Hz are reference values.
• For the external current sensor range, add 100
µ
V to the current accuracy and (100
µ
V/external current sensor range rating)
× 100% of range to the power accuracy.
• For n
th
order component input, add ({n/(m + 1)}/50)% of (the n
th
order reading) to the n + m
th
order and n – m
th
order of the
voltage and current, and add ({n/(m + 1)}/25)% of (the n
th
order reading) to the n + m
th
order and n – m
th
order of the power.
• Add (n/500)% of reading to the n
th
component of the voltage and current, and add (n/250)% of reading to the n
th
component of
the power.
• The accuracy when the crest factor is 6 is the same as the accuracy when the crest factor is 3 after doubling the measurement
range.
• The guaranteed accuracy ranges for frequency, voltage, and current, are the same as the guaranteed ranges for ordinary
measurement.
If the amplitude of the high frequency component is large, influence of approximately 1% may appear in certain orders.
Because the influence depends on the size of the frequency component, if the frequency component is small with respect to
the range rating, the influence is also negligible.
Delta Computation Feature
Item Delta Computation Setting Symbols and Meanings
Voltage (V) Difference Δ
F1[Udiff]
Differential voltage between U1 and
U2 determined through computation
3P3W->3V3A Δ
F1[Urs]
Unmeasured line voltage computed in
a three-phase, three-wire system
Delta->Star Δ F1[Ur], Δ F2[Us], Δ F3[Ut] Phase voltage computed in a three-
phase, three-wire (3V3A) system
Star->Delta Δ
F1[Urs],
Δ
F2[Ust],
Δ
F3[Utr] Line voltage computed in a three-
phase, four-wire system
Current (A) Difference Δ
F2[Idiff]
Differential current between I1 and I2
determined through computation.
3P3W->3V3A Δ
F2[It]
Unmeasured phase current
Delta->Star Δ
F4[In]
Neutral line current
Star->Delta
Δ F4[In]
Neutral line current
14.6 Functions