YOKOGAWA wt3000 User Manual

12-8 IM 760301-01E
Item Specifications
Effective input range • 0 to ±130% of the power range (see section 5.2) for DC measurement.
• ±130% of the power range for current measurement when the voltage and current are in the
range of 1 to 130% of the measurement range. However, if the data update interval is 50 ms,
100 ms, 5 s, 10 s, or 20 s, the signal level of the synchronization source must satisfy the input
signal level of frequency measurement (see section 12.5).
* 110% for the maximum range of direct voltage and current inputs. The accuracy for 110% to
130% of the measurement range is reading error × 1.5.
Lower limit of Same as the lower limit of measurement frequency for voltage and current.
measurement frequency
Power factor (λ) influence • When λ = 0
•5 mA to 200 mA range of a 2-A input element
• Apparent power reading × 0.1% in the range of 45 to 66 Hz.
• For other frequency ranges, see below. However, the figures are reference values.
Add apparent power reading × (0.1 + 0.05 × f (kHz))%
• 500 mA to 2 A range of a 2-A input element or 30-A input element
• Apparent power reading × 0.03% in the range of 45 to 66 Hz.
• For other frequency ranges, see below. However, the figures are reference values.
Add apparent power reading × (0.03 + 0.05 × f (kHz))%
• When 0 < λ < 1
(Power reading) × [(power reading error %) + (power range error %) × (power range/apparent
power indication value) + {tan φ × (influence when λ = 0)}] where φ is the phase angle between
the voltage and current.
Line filter influence When the cut-off frequency is 500 Hz
45 Hz ≤ f ≤ 66 Hz: Add 0.3% of reading. f < 45Hz: Add 1% of reading.
When the cut-off frequency is 5.5 kHz
f ≤ 66 Hz: Add 0.3% of reading. 66 Hz < f ≤ 500 Hz: Add 1% of reading.
When the cut-off frequency is 50 kHz
f ≤ 500 Hz: Add 0.3% of reading. 500 < f ≤ 5 kHz: Add 1% of reading.
Temperature coefficient Same as the temperature coefficient for voltage and current.
One year accuracy Add (reading error of accuracy at 6 months × 0.5) to the accuracy at 6 months.
Accuracy when the crest Accuracy obtained by doubling the measurement range error for the accuracy when the crest factor
factor is set to 6 is set to 3
Accuracy of Other Parameters and Computation Accuracy
• Accuracy of apparent power S Voltage accuracy + current accuracy
• Accuracy of reactive power Q Accuracy of apparent power +
(1.0004 – λ
2
) – ( (1 – λ
2
))×100%
of range
• Accuracy of power factor λ ±[(λ – λ/1.0002) + |cosφ – cos{φ + sin
– 1
(influence
from the power factor when λ = 0%/100)}|] ± 1 digit when
voltage and current is at rated input of the measurement range
• Accuracy of phase difference φ ±[|φ – cos
– 1
(λ/1.0002)| + sin
– 1
{(influence from the power
factor when λ = 0%)/100}] deg ± 1 digit when voltage and
current is at rated input of the measurement range
• For the accuracy of frequency fU and fI, see “Frequency Measurement” in section 12.5,
“Functions.”
• For the accuracy of measured values WP, WP+, WP-, q, q+, and q- and the integration time, see
“Integration” in section 12.5, “Functions.”
• For the accuracies of voltage, current, and power during harmonic measurement; the accuracies
of rotating speed and torque; and the accuracy of D/A output; see the respective sections in the
Expansion Function User’s Manual IM760301-51E .
12.4 Accuracy

YOKOGAWA wt3000 Specifications

General

Brand	YOKOGAWA
Model	wt3000
Category	Measuring Instruments
Language	English