# Save Energy (Money) by a simple monitoring test.

Southern testing has amongst its testing equipment power analysers, these instruments analyse the way your installation is using the power you pay for. Simply put you pay for Volts x Amps = Kva however Kw are the sum of Volts x Amps x PF. PF = cosΦ or the relationship of the phase angle of the voltage and amperage. Most domestic installations do not need to worry about this however commercial and industrial installations generally benefit by having this checked. A normal installation that does not have a significant load from motors,fluorescent lights or computers (All inductive load) will have a PF >.9 (more or less 90% efficient use of power).

A recent survey revealed a PF of .51 on an installation using 5000KW a day,after PF correction was installed the use dropped to 3850Kw per day,you can calculate the savings on what ever you are paying per unit of electricity.

### For the technically minded.

Apparent Power and Actual Power

The mathematical relationship between actual power and apparent power is shown by means of a vector diagram, Figure 5. The line AB is the reference point for voltage and measures the actual power. If the current is in phase with the voltage, then the apparent power is equal to the actual power, and the power factor is 1.0. This would be true of circuits with only resistive loads, such as electric heaters. All inductive devices, such as motors, transformers, and solenoid coils require magnetizing current to create the magnetic field necessary for the device to operate.

This magnetizing current, or reactive current as it is termed, does not produce usable power, but the effect of the magnetic field is to cause the current drawn from the power line to lag the voltage. The term reactive power is used to describe the product of the reactive current and the operating voltage,and is measured by line BC. The greater the reactive current, in proportion to the useful current, the greater the reactive power and the lower the power factor. The apparent power (volt-amperes) is measured by line AC. The symbol Φ or q (theta) is conventionally used to denote the power factor angle.

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