Posted 07 May 2012 - 10:28 AM
Dear Mark,
After arrangement of a Disc type energy meter, I did again tests of 7 different brands UPSs and still faced problem in measurement of non-sinusoidal output energy of UPS. Here are results of test of two UPS.
Pedestal fan 150W checked on utility power. Voltage and current measured by a very good quality true RMS digital meter.
V = 218V
I = 0.685A
P1 = 131W (measured by a digital energy meter)
P2 = 140W (measured by a needle type analog energy meter)
P3 = 130W (measured by a disc type energy meter)
UPS 1 (square wave type) with pedestal fan 150W
Input power to UPS
V = 23.05A, I = 10A, P = 231W (V x I)
Output power of UPS to fan
V = 222V, I = 0.89A,
P1 = 162W (measured by a digital energy meter)
P2 = 160W (measured by a needle type analog energy meter)
P3 = 148W (measured by a disc type energy meter)
UPS 2 (near to sign wave type) with pedestal fan 150W
Input power to UPS
V = 11.91V, I = 16A, P = 191W (V x I)
Output power of UPS to fan
V = 201V, I = 0.735A,
P1 = 172W (measured by a digital energy meter)
P2 = 142W (measured by a needle type analog energy meter)
P3 = 133W (measured by a disc type energy meter)
Now I am still confused which output power should I use to calculate the efficiency.
"Don't assume any thing, always check/ask and clear yourself".