Section 7: Model 9100: Specifications
7-31
Final Width = 215mm
7.19.10 Calculating Power Uncertainty
The Power Uncertainty is based on the root sum square (rss) of the following three uncertainties (expressed in %):
1. Voltage (Main) Channel Amplitude Uncertainty
2. Current (Auxiliary) Channel Amplitude Uncertainty
3. Amplitude Uncertainty due to Phase Error
Power Uncertainty = U
2
Voltage
+ U
2
Current
+ U
2
Phase
The following examples demonstrate how to calculate the power uncertainty at a specific calibration point.
(Note: All specifications used are 1 year specifications).
Example 1:
Calibrator Output 100V, 3A (at 60Hz) Power Factor 1.0 (Ø = 0
°
).
1. Voltage Amplitude Uncertainty (From Section 7.4.1)
100V Specification :
= 0.04%Rdg
+
6.3mV(Floor)
= 0.04%
+
(6.3mV/100V) x 100
= 0.04%
+
0.0063%
= 0.0463%
2. Current Amplitude Uncertainty (From Section 7.19.7)
3A Specification :
= 0.08%Rdg
+
480
µ
A(Floor)
= 0.08%
+
(480
µ
A/3A) x 100
= 0.08%
+
0.016%
= 0.096%
3. Amplitude Uncertainty due to Phase Error (From Section 7.19.9)
Specifications:
Voltage Channel Phase Uncertainty
0.07
°
Current Channel Phase Uncertainty
0.08
°
Combined Phase Uncertainty
Ø
ERROR
= 0.07
°
+
0.08
°
= 0.15
°