Power Factor Correction
Power factor measures how effectively current is converted into useful work; low power factor incurs utility penalties and reduces system capacity.
Inductive loads (motors, transformers) draw magnetizing current that does not produce real power, resulting in a power factor below 1.0, typically 0.7–0.9 at plants without correction.
Many utilities charge penalties for power factor below 0.95; capacitor banks are the typical correction method, sized to bring the plant's overall power factor up.
Power factor correction capacitors require periodic inspection — swelled cases, leaking oil, or visible bulging indicate failure, which can cause the capacitor to short and damage the system.
Synchronous motors (used on some very large pumps and blowers) can correct power factor by varying excitation — sometimes the most cost-effective correction, particularly if the motor runs continuously.
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