Power supply units are nowadays made to work on almost every power grid and their efficiency differs depending on the input voltage. We did not want to restrict our testing on a 230VAC power grid, therefore we acquired a common 3KVA laboratory VARIAC. The VARIAC allows us to adjust the input voltage between 0 and 260VAC, giving us the ability to test the performance of all power supplies at both 110VAC and 230VAC input.
Between the VARIAC and the power supply we installed our single phase Lutron DW-6091 power analyzer. The power analyzer allows us to take readings of the input apparent power, real power, input voltage and frequency and of the power factor of the power supply, all of which are transferred directly to our software via its RS232 interface. The Lutron DW-6091 is a class G 1.5 measuring instrument, meaning that all results are 1.5% accurate or better.
Lutron DW-6091 Power Analyzer