This phase difference can take two basics forms.
- The current can “lag” the voltage when an inductive load (i.e., motors, magnetic HID ballasts) is used or
- The current can “lead” the voltage when a capacitive load(i.e., computers, electronic fluorescent ballasts) is used.
When the current is out of phase with the voltage,the power utility has to supply more volt-amperes(VA) for a given wattage (W). Certain customers, such as industrial companies, may have to pay an additional charge if their power factor is too low which is why many industrial applications have banks of capacitors. These capacitors correct the poor power factor caused by the motors. This is also how manufacturers have been able to take a product that is inductive in nature, such as a magnetic HID ballast with a normal power factor, and include a “power factor correcting” capacitor to give the ballast a high power factor.
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