All you really need to know is that the technology works (actual results) but the following terms and definitions may be helpfull in understanding PowerwoRx.
Electrical Terms and Definitions
Alternating Current (AC):
The flow of electrons in a conductor measured in amperes. Alternating current reverses its direction of flow in a cyclical
manner; i.e. 60 cycles per second. Conversely, direct current always flows in the same direction at 0 cycles per second.
Amperes (Amps):
The unit measure for the flow of current in a conductor (analogous to gallons per minute in a piping system).
Voltage (Volts):
The measurement of the electromotive force or potential which will make electrons flow in a conductor or circuit.
Watt, Kilowatts, Kilowatt Hours:
Electrical power consumption is measured in watts.
A Kilowatt is 1000 watts. A Kilowatt Hour is 1000 watts used for one hour.
We are concerned with true power which is the measure of power actually used by the load as measured by the utility watt
meter and our T.I.F. meter.
In pure resistive A/C circuit, power could be calculated by measuring the voltage across the phase conductors and
multiplying by the current flowing through the circuit conductors with an amp meter. To measure true power in inductive
circuits power factor must be considered.
KVA (Kilovolt Amperes):
KVA is the non power measure of the voltage multiplied by the amperes.
KVA is not a measure of true power it is a measure of the level of apparent power a generator or transformer could deliver to
a circuit with a power factor of one.
To convert from apparent power to true power, you must tae the KVA and multiply it by the power factor. For example, 100
KVA of measured apparent power serving an inductive load with a power factor of .9 would result in a real power of 90 KW.
If Kilowatts (KW) are the measure of true or real power available for work then KVA is a measure of apparent power needed
to get the true power to the work.
From a utility's point of view they are generating power with a power factor of one.
In other words the KW and KVA at the outlet of the power plant is the same value.
As the power factor is degraded by load and transmission factors it takes proportionally more KVA per KW used to create and
deliver to the consumer true or USABLE power.
The effect that a lagging power factor has on the utility is then to force it to generate more apparent power to satisfy our
clients' needs for true or USABLE power.
In other words, if we measure a power facto of 1.0, then each KVA is being turned into a KW and the real and apparent
power are equal.
If the power factor is .5 then each KVA supplied to the transformer by the utility results in one half of one KW of real power
being consumed and measured. This means the utility has to absorb the difference in real vs. apparent power.
The affect on the utility supplying power to a network of customers with lagging or poor power factor is that its generating
and distribution efficiency is reduced.
Because the current being generated by the utility has to increase as the demand for KVA increases and in a poor power
factor network the current increases disproportionately faster than in a network with unity power factor, then the losses due
to the resistive heating in the power distribution network of conductors increases.
The term most frequently used to express this problem is W=I2 R meaning that conductor, transformer and motor heating
increase at the rate of the amperes squared time the resistive component of the circuit. Some customers are penalized for
low power factor by being charged for the difference between KVA and KW.
PowerwoRx e3 reduces the I2 R losses by
improving power factor and reducing KW.
KVA(R):
The measure of the amount of reactive KVA that is necessary to raise a lagging power factor toward unity.
Harmonic Interference:
AC power is delivered throughout the distribution system at a fundamental frequency of 60 Hz. (50 Hz in Europe.) Harmonics
are defined as, "integral multiples of the fundamental frequency."
For instance, the 3rd harmonic frequency is 180 Hz, the
5th is 300 Hz, etc. In the US, the standard distribution system in commercial facilities is 208/120 wye.
There are three phase
wires and a neutral wire. The voltage between any two phase wires is 208, and the voltage between any single phase wire
and the neutral wire is 120. All 120 volt loads are connected between a phase and neutral.
When the loads on all three
phases are balanced (the same fundamental current is flowing in each phase) the fundamental currents in the neutral cancel
and the neutral wire carries no current.
When computer loads and other loads using switched mode power supplies are
connected, however, the situation changes.
Switch mode power supplies draw current in spikes, which requires the AC supply to provide harmonic currents.
The largest
harmonic current generated by the SMPS is the 3rd. The magnitude of this harmonic current can be as large or larger than
the fundamental current.
Also generated, in smaller amounts, are the 5th, 7th, and all other odd harmonic currents.
Like the fundamental current, most harmonic currents cancel out on the neutral wire. However, the 3rd harmonic current,
instead of canceling, is additive in the neutral.
Thus if each phase wire were carrying, in addition to fundamental current,
100 amps of 3rd harmonic current, the neutral wire could be carrying 300 amps of 3rd harmonic current. In many cases, neutral-wire current can exceed phase wire currents. This extra current provides no useful power to the loads. It simply reduces the capacity of the system to power more loads, and produces waste heat in all the wiring and switchgear.
When the 3rd harmonic current returns to the transformer it is reflected into the transformer primary where it circulates in the delta winding until it is dissipated as heat. The result is overheated neutral wires, switchgear, and transformers. This can lead to failure of some part of the distribution system and, in the worst case, fires. In addition, waste heat in all parts of the system increases energy losses and results in higher electrical bills. Third harmonic currents can increase electrical costs by as much as 8%
Circuit:
A closed loop consisting of conductors (wires) from a source of voltage (a transformer in our case) to a load (motors,
fluorescent lamp ballasts or resistive loads) that provides the path for the flow of current through the load.
Phase:
Phase is a trigonometric measure of the angle between the 60-cycle wave current form and the 60-cycle voltage wave form.
In a perfect world, the current wave form and the voltage wave form leaving a generator would start at the same time.
In reality, the inductive characteristics of the electrical distribution system and the inductive loads imposed on it retard the
current wave form and cause it to lag the voltage wave form (If a circuit had more capacitance, then inductance the current
wave form) would lead to the voltage wave form.
Inductive Load:
In general loads that operate by the passing of alternating currents through a coil of wire wound around an iron core. The
resulting magnetic field is used to:
a - cause a motor shaft to rotate, or
b - induce a similar current in another coil of wire wound around the same piece of iron core as in a transformer
(There are inductive heaters that are coils of wire wound around the media to be heated.)
Resistive Load:
A load that turns all energy (current and voltage) applied to it into heat.
Includes incandescent lamps, space heaters,
immersion heaters, etc.
These loads are not inductive.
Power Factor:
When current and voltage wave forms start at the same time they are in phase and power factor is 1. As circuit inductance
retards the current wave form it falls out of phase or lags the voltage wave form.
The measure of a lagging current wave form is expressed as a percentage; i.e., if the current lags the voltage by 10%, the
power factor is 100% less 10% or 90% or 0.90.
Effects of low power factor:
It is sometimes considered that the wattless component of a current at low power factor is circulated without an increase
of mechanical input over that necessary for actual power requirements. This is inaccurate because internal work or losses
due to this extra current produced and must be supplied by the utility.
Since these extra losses manifest themselves in heat,
the capacity of the distribution network is reduced. Moreover, wattless components of current heat the line conductors, just
as do energy components, and cause losses in them.
The loss in any conductor is always
W=I2R
where W = the loss in watts, I = the current in amperes in the conductor, and R = the resistance in ohms. It requires much
larger equipment and conductors to deliver a certain amount of power at a low power factor than at a power factor close to 1.
Transformer (Voltage Type):
Inductive devices used to isolate the flow of current in one circuit from another while allowing magnetic coupling of the two
circuits to create a voltage in the second circuit. Transformers may be used to step down a voltage from a higher level to a
lower level or to step up a voltage from a lower level to a higher level or to maintain the same voltage on both sides
(primary and secondary) while isolating the circuits from one another. Fluorescent lamp ballasts are transformers.
Capacitance:
A measure of a circuit or device's ability to store electrical energy. Applied primarily to A/C circuits where the alternating
nature of the current charges and discharges the capacitor as the current reverses its direction of flow in the circuit.
Capacitors ability to store electricity is measured in "Farads" or increments thereof as in microfarads. Capacitors are used to
improve the performance of certain inductive circuits as discussed under power factor.
Electro Magnetic Field (EMF):
Technically, the term "electromagnetic field" (EMF) refers to all fields throughout the electromagnetic spectrum. In common
usage, however, the term usually refers to so-called extremely low-frequency nonionizing radiation fields—those fields below
300 Hertz (Hz)—and often only to those fields in the 50 to 60 Hz range, which are also known as power-frequency EMFs.
As
a type of nonionizing radiation, EMFs in this range do not have sufficient energy to remove an electron from an atom or
molecule, but generally transfer thermal energy to other particles. Power-frequency EMFs are those generated by electric
power delivery systems—those for which there has been the greatest public concern and research about possible adverse
human health effects.
Power-frequency EMFs have two components: electric fields and magnetic fields. The electric fields are generated from
potential energy, or the presence of voltage on a power line.
The magnetic fields, on the other hand, are generated from the
actual electrical current, or the flow of electricity. Thus, when a standard household electric light is plugged into a live
electrical socket, but turned off, it generates only an electric field. Once turned on, it generates both electric and magnetic
fields, since the voltage is still present but current is now flowing. The size of a magnetic field increases as the amount of
current flow increases, as the size of the source increases, and as one gets nearer to the source.
Metal Oxide Varistor (M.O.V.):
A discrete electronic component that is commonly used to divert excessive current to the ground and/or neutral lines. Acting
like a pressure relief value, an MOV is comprised of zinc oxide with small quantities of bismuth, cobalt, manganese and other
metal oxides.
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