18 years ago
the supply line capacity to supply power. Adding PF correction capacitors of
the right amount balances out the inductive reactance by capacitive
Does the effect of poor power factor show at the generator? I would say yes
because of the extra heat generated in the wires (conservation of energy).
If so, is that the only extra torque the generator needs is to over come the
extra heat loss in the lines from low power factor?
Although the transformer's capacity is also reduced by the effects of
lagging current, does the lagging current pass though the transformer to the
I see some devices, such a equipment with a diode bridge and capacitor to
rectify and filter the AC supply to DC. These are rated to have low power
factor because the asymmetrical current draw due to very high crest factor
from the charching of the capacitor near the peak voltage. The current isn't
lagging, just distorted. Are they generalizing terms by calling devices with
high crest factor to be of low power factor? (i.e. It draws more VA than
real power consumed so it has a lower than 1.0 power factor)
In an experiment, I added 2uf of capacitance to a 9 watt magnetically
ballasted fluorescent lamp. This brought the measured VA of 18 down to 11
which seems like the power drawn should be (9 watts plus 2 watts lost in the
ballast). When I scoped the current wave form it had a distinct double hump
(not unlike the top part of the heart symbol). Wouldn't this asymmetry still
cause issues with utility equipment (transformers and such)?