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How EEF Power Saving Devices Work

Here is the technical explanation of how the EEF Power Saving technology saves you money on your utility bill. All induction loads require two types of power, one is KVAR, referred to as reactive power and the other is KW referred to as working power. The combination of KVAR and KW make up KVA, referred to as apparent power. The relationship between the three is explained in the attached power point presentation. KVA is what the utility company charges you for. Induction loads require KVAR to establish the EMF (electromagnetic field) around the induction windings. The EMF provides the torque necessary to turn the motor shaft. Without KVAR (reactive power) the motor would not run. Only after you have established the EMF around the motor induction windings will the motor shaft then turn. The power that is used to turn the shaft on a motor which turns pump impellers or fan blades etc. is called the working power or KW. By implementing the KVAR technology or custom sized capacitors to individual induction loads you are providing the necessary KVAR for that load and therefore the power you buy from your utility company is mostly KW, working power.

You can see the proof of this in several ways. You can compare last years bill in one month without KVAR to this year’s bill in the same month with KVAR installed. This is the proof that you are paying for both KVAR and KW and by implementing the KVAR technology you will be paying for KW therefore reducing your energy consumption from the utility plant and in turn your utility bill.

Induction loads require KVARs to run and requires KW to turn the motor shaft, the difference is that the KVAR technology provides the KVAR’s locally to the motor so that most of the power pulled from the utility company is KW, working power.

Let's take a moment to explain power factor. Power factor is a measurement of how efficiently power is used by a load. This is also explained mathematically in the attached power point presentation. Power factor is equal to the ratio between KW (working power) and KVAR (reactive power). It is represented like this:

PF= kw / KVAR (power factor is equal to KW divided by KVAR)

Some large commercial customers are charged power factor penalties by the power utility companies if their power factor drops below a certain number. If the power utility company did not measure or charge you for delivering KVAR then how can they panelize these large companies for it? The answer is the power utility company does deliver KVAR to their customers and they charge all their customers for this service. Only some large commercial companies get charged an additional charge called power factor penalties if their power factor drops below a certain point. All customers pay for KVARs.

So what is power factor? Let’s say that we measure the power factor on a load and it measures 70% or .70. Based on the formula above, that means that 70% of the power that the motor is pulling is being used to do work like turn a pump or fan, represented by KW (working power) and the other 30% of the power that is being pulled from the utility power company is being used to establish the EMF around the motor windings called KVAR (reactive power). The reason we say that this motor is 70% efficient is because only 70% is being used to produce an output like turning a fan or pump. The other 30%, which is being used to establish the EMF around the motor windings, is not producing any output or work for you, but you are paying for it. KVARs are a necessity for all induction loads but they do not produce any work and therefore power factor measures how much of the power you use from the utility company is used to produce work or an output and how much is used to establish the EMF around the induction windings.

The KVARs needed for an induction motor is the same whether the motor is loaded or not so when a motor is not loaded the power factor is low and as the motor load increases the power factor improves. Let’s look at this a little closer. Power factor is the ratio of KW divided by KVAR. Let’s remember that the required KVARs for a motor are the same whether it is unloaded or loaded. So when a motor in unloaded it is basically running or free wheeling but not turning a fan or pump and therefore it is not pulling a lot of KW (working power) because it is not doing much work. In this example the power factor will be low because KVARs will be higher than KW and the ratio between the two make up power factor. Now let’s take the same example except this time the motor is loaded. When the motor is turning a load it will have to pull more power to turn that load so it is now pulling more KW’s (working power). As KW goes up and KVAR does not change the power factor goes up as well. That is the reason a loaded motor has a better power factor than an unloaded motor but that does not changed the fact that the motor still has the same requirements for KVARs to establish the EMF in order to turn the motor shaft and produce an output.

When power factor goes up, amps and KVAR goes down. This is partially true. We are going to look at two examples one where you have not installed the KVAR technology and the other where you have installed the KVAR technology. First we will look at an example where you have not installed the KVAR technology. As in the example above the KVARs required to run the induction load does not change so you would have to load the motor and increase KW to improve power factor. So in this case KW went up in order for the power factor to go up. Now let’s assume that the KVAR technology is installed. Run the motor and measure the power factor downstream of the KVAR unit and upstream of the KVAR unit. You will find that the power factor upstream of the KVAR unit is close to unity or 100% power factor and the power factor downstream of the KVAR unit is the same as it is if the KVAR unit was not installed. The reason being is when you measure power factor upstream of the KVAR unit and it is measuring close to 100% without having to increase KW means that you are pulling only KW from the utility and not KVAR and therefore power factor is equal to KW. The KVAR (reactive power) required to run that motor is delivered to the motor by the KVAR unit and not the utility company.

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