Examples Of Specified Power Uncertainties At Various Output Settings; Calculate Power Uncertainty - Fluke 5502A Operator's Manual

5502A
Operators Manual

Examples of Specified Power Uncertainties at Various Output Settings:

Voltage Current
Setting Setting
(Volts) (Amps)
+10.000 +0.500.000
15.000 +2.0000
100.000 +20.000
1000.00 20.000
120.000 1.00000
120.000 1.00000
240.000 1.00000
240.000 1.00000
1000.00 20
1000.00 20
1000.00 20
100 0.30
100 0.30
[1] Add 0.02 % unless a settling time of 30 seconds is allowed for output currents >10 A or for currents on the highest two current
ranges within 30 seconds of an output current >10 A.

Calculate Power Uncertainty

Overall uncertainty for power output in watts (or VARs) is based on the root sum square (RSS) of the individual
uncertainties in percent for the selected voltage, current, and phase parameters:
Watts uncertainty
VARs uncertainty
Because there are an infinite number of combinations, you must calculate the actual ac power uncertainty for your
selected parameters. The method of calculation is best shown in the subsequent examples (with 1-year specifications):
Example 1 Output: 100 V, 1 A, 60 Hz, Power Factor = 1.0 (Φ=0).
Voltage Uncertainty Uncertainty for 100 V at 60 Hz is 0.050 % + 3 mV, totaling: 100 V x .0.0005 = 50 mV added to
3 mV = 53 mV. Expressed in percent: 53 mV/100 V x 100 = 0.053 % (see "AC Voltage (Sine Wave) Specifications").
Current Uncertainty Uncertainty for 1 A at 60 Hz is 0.05 % +100 μA, totaling: 1 A x 0.0005 = 500 μA added to
100 μA = 0.6 mA. Expressed in percent: 0. 6 mA/1 A x 100 = 0.06 % (see "AC Current (Sine Waves) Specifications").
Phase Uncertainty (Watts) Adder for PF = 1 (Φ=0) at 60 Hz is 0 % (see "Phase Specifications").
Total Power Uncertainty =
Example 2 Output: 100 V, 1 A, 400 Hz, Power Factor = 0.5 (Φ=60)
Voltage Uncertainty Uncertainty for 100 V at 400 Hz is 0.050% + 3 mV, totaling: 100 V x .0.0005 = 50 mV added to
3 mV = 53 mV. Expressed in percent: 53 mV/100 V x 100 = 0.053 % (see "AC Voltage (Sine Wave) Specifications").
Current Uncertainty Uncertainty for 1 A at 400 Hz is 0.05 % +100 μA, totaling: 1 A x 0.0005 = 500 μA added to
100 μA = 0.6 mA. Expressed in percent: 0. 6 mA/1 A x 100 = 0.06 % (see "AC Current (Sine Waves) Specifications").
Phase Uncertainty (Watts) Adder for PF = 0.5 (Φ=60) at 400 Hz is 2.73 % (see "Phase Specifications").
Total Power Uncertainty =
VARs When the Power Factor approaches 0.0, the Watts output uncertainty becomes unrealistic because the dominant
characteristic is the VARs (volts-amps-reactive) output. In these cases, calculate the Total VARs Output Uncertainty, as
shown in example 3:
Example 3 Output: 100 V, 1 A, 60 Hz, Power Factor = 0.174 (Φ=80)
Voltage Uncertainty Uncertainty for 100 V at 60 Hz is 0.050% + 3 mV, totaling: 100 V x .0.0005 = 50 mV added to
3 mV = 53 mV. Expressed in percent: 53 mV/100 V x 100 = 0.053 % (see "AC Voltage (Sine Wave) Specifications").
Current Uncertainty Uncertainty for 1 A at 60 Hz is 0.05 % +100 μA, totaling: 1 A x 0.0005 = 500 μA added to
100 μA = 0.6 mA. Expressed in percent: 0. 6 mA/1 A x 100 = 0.06 % (see "AC Current (Sine Waves) Specifications").
1-22
Selected Output Settings
Phase Phase
Frequency
Setting Setting
Hz
(units of PF) (Degrees)
DC
DC
DC
DC
60 1
60 0.766
50 1
50 0.766
55 1
55 0.766
55 -0.906
30000 1
30000 0.766
= +
2 2
U U U
Power Voltage
= +
2 2
U U U
VARs Voltage
= 2 +
U . 0 053 . 0
power
= 2 +
U . 0 021 . 0 06
power
Absolute Uncertainty as
specified for tcal ±5 °C, ±(% of
Selected
Power U
Voltage
(Watts)
5 0.00550 % 0.04680 %
30 0.00533 % 0.03220 %
2000 0.00600 % 0.10375 %
20000 0.00565 % 0.10375 %
0.0 120 0.05250 % 0.06000 % 0.000 %
40.0 91.92 0.05250 % 0.06000 % 0.220 %
0.0 240 0.05125 % 0.06000 % 0.000 %
40.0 183.84 0.05125 % 0.06000 % 0.220 %
0.0 20000 0.05200 % 0.14500 % 0.000 %
40.0 15320 0.05200 % 0.14500 % 0.220 %
-25.0 18120 0.05200 % 0.14500 % 0.122 %
0.0 30.0 0.12900 % 0.4667 %
40.0 22.98 0.12900 % 0.4667 % 25.128 %
+
2
U
Current Phase
+
2
U
Current Phase
2 + 2 =
06 0 . 0 080 %
2 + 2 =
. 2 73 . 2 73 %
Absolute
Uncerainty
output setting)
Watts)
U U
Current Phase
0.047 %
0.033 %
0.104 %
0.104 %
0.080 %
0.234 %
0.079 %
0.234 %
0.154 %
0.269 %
0.196 %
3.407 % 3.442 %
25.133 %
Power
±(% of
[1]
U
Power