Power Factor Terminology

Power Factor Terminology, because now you understand the concept of Power Factor and a Power Factor Correcting Capacitor, is something that you are ready for (exciting!). After that ...."The Power Triangle".

Load Current is also referred to as Real Current because its the component of current thats really doing the work. (Remember? The magnetizing current only builds a magnetic field, the load current is associated with driving the load.)

If the current peaks before the applied voltage, it is said to be Leading Current. If the current peaks after the voltage, it is referred to as Lagging Current.

Capacitor Current and Magnetizing Current, which leads and lags (respectively) the voltage by 90 degrees, is also called Reactive Current or Imaginary Current (I wish they wouldn't call it "Imaginary" because it really does happen).

The Total Motor Current (or total current delivered to a set of loads, like a building) which is the instantaneous sum of the Real Current and Reactive Current, is also called the Apparent Current (remember, 1 amp + 1 amp = 2 amps of RMS current ONLY IF THEY ARE IN PHASE WITH EACH OTHER).

Power Factor Terminology often focuses on load and power. If we multiply the Real Current (the current that drives the load) by the system voltage we get the Real Load or Real Power. The units of Real Load, or Real Power, are Watts (i.e. kW, MW, etc.)

If we multiply the Reactive Current (the current thats associated with storing and releasing energy for magnetic fields) by the system voltage we get the Reactive Load or Reactive Power, which is also called Imaginary Load. Its called Imaginary Load because its really not a load....it consumes no energy, but rather swaps it during every cycle from one storage device (magnetic field) to another (capacitor or generator), similar to how a pendulum continuously changes from potential to kinetic energy and back. The units of Reactive Load or Reactive Power are VARs, which stands for Volts-Amps-Reactive (i.e. kVAR, MVARs, etc.)

If we multiply the Apparent Current (the total current delivered to the load) by the system voltage we get the Apparent Load or Apparent Power. The units of Apparent Load are VA, for Volt-Amps (i.e. kVA, MVA, etc.). Apparent Power is a combination of work-related current and non-work related current. Many devices, including transformers, are rated in VA, which is really their current carrying ability at the system voltage (regardless of how much of the current is driving a load vs. building a magnetic field).

Power Factor Terminology is important because EEs are always trying to squeeze these words into a conversation. This might be a good page to print and read every night before bed (like EEs do).

Now that we understand Power Factor Terminology, lets go on to the ....Power Factor TRIANGLE.