Question: when measuring current with a threewire wattmeter my calculated current...
When measuring current with a three-wire wattmeter, my calculated current has a % Error of 23% at 7 volts, 14% at 9 volts, and 6% at 11 volts versus the amperage measured by the wattmeter. Ultimately, I would like to understand why this is the case so I can best answer the question:
1) "What are some reasons for this?"
Though, I would also like to understand two other things:
2) How does a three-wire wattmeter reading differ from that of a four-wire wattmeter in terms of accuracy, current distribution, and anything else I should know?
and 3) Why would the accuracy for the three-wire wattmeter improve as the voltage increases?