M
Moog
The course I am taking for 2330 yr2 has a pratical test on a fluresent lamp the readings taken were for voltage across the choke, luminare and Current, Power at supply. These values taken with and without the capacitor. The Circuit was basically the choke and luminare in series on one leg of a parallel circuit and a pf correction capacitor on the other leg. We were asked to comment upon the recorded readings and the calculated values. To be able to say anything about the calculations, I would have thought that the current in each leg of the parallel circuit would have to be measured, this was not done. The current was only taken before the parallel circuit, and as this current would split down either leg the volts drop across luminare and choke could not be used to calculate the power disipated as we don't know the current in that leg of the circuit. The lecturer explained that in real life we would not bother with the power disipated across the choke and luminare but use a pf of 0.85 and 1.8x current usage to estimate the circuit requirements. Fair enough, but what does this test prove then? It does not make sense to me, I would have thought that proving the 0.85 pf estimate by calculating the W and VA for the choke and luminare would require the current in each leg. Am I missing something?
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