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Common terms used when discussing generators:
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An electric current that reverses direction at regular intervals, having a magnitude
that varies continuously in sinusoidal manner. Abbreviation - A/C See Also -
Direct Current.
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The strength of an electric current measured in amperes. Abbreviation - amp.
Amps = watts/volts
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The amount by which a voltage or current changes from zero or an average
value. The maximum deviation of an alternating current from its average value.
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A normal multimeter can measure volts, electrical pressure, and amps, electrical
current. The product of these two measurements is apparent power, because it
is the apparent power transfer. Apparent power is measured in volt-amps (or
Kilovolt-amps KVA), because it is the product of volts (root-mean-squared) and
amps (also root-mean-squared). The problem with a multimeter is that it
averages these quantities over time.
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Decibels:
A unit used to express the
intensity of a sound wave.
Abbreviation - dB. See chart
on right for common dB levels
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Direct Current:
An electric current of constant
direction, having a magnitude
that does not vary or varies
only slightly. Abbreviation -
D/C See Also - Alternating
Current
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Frequency:
The rate at which a repeating
event occurs, such as the full
cycle of a wave. Frequencies
are usually measured in
hertz. Abbreviation - freq.
See Also - Hertz, Amplitude
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Hertz:
The international unit of
frequency: One cycle per
second. Abbreviation - Hz.
Household current in the
United States is 60 Hz
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Kilowatts (kW):
A unit of power equal to 1000
watts. (Real Power)
Abbreviation - kW. See also
Watts
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Kilovoltampere (KVA):
A volt-ampere in electrical terms is the amount of power in an alternating current
circuit equal to a current flow of one ampere at an electrical force of ove volt. It is
equivalent to watts for non-reactive circuits and in the strictest sense is identical,
but by convention the two are used as units for subtly different physical
quantities. While the KVA and the Kw are dimensionally equivalent on may find
products rated in both with different numbers. This is common practice on
uninterruptible power supplies (UPS). The KVA rating is the apparent power that
a UPS is capable of producing, while the Kw rating is the real power it is capable
of producing. KVA divided by the Kw is referred to as the power factor.
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Load:
The power delivered by a generator. Also the devise that receives the power.
When you power a device with a generator you place a load on the generator,
the device being powered is the load.
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Power Factor:
The ratio of real power (kW) flowing to the load to the apparent power, and is a
number between 0 and 1 frequently expressed as a percentage. Due to energy
stored in the load and returned to the source, or due to a non-linear load that
distorts the wave shape of the current drawn from the source, the apparent power
can be greater than the real power. In an electric power system, a load with low
power factor draws more current than a load with a high power factor for the
same amount of useful power transferred. The higher currents increase the
energy lost in the distribution system, and require larger wires and other
equipment.
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Real Power:
Real power is measured in watts (also Kilowatts kW). As the waves of current and
voltage coincide less, less real power is transferred.
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Sinusoid (Sine Wave):
Graphing the voltage of an alternating current gives a sine wave pattern.
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Standby:
A generator that provides power when conventional power is interrupted.
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Volt:
The international system unit of electric potential and electrovotive force, equal to
the difference of electric potential between two points on a conducting wire
carrying a constant current of one ampere when the power dissipated between
the points is one watt.
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Watt:
In electricity a watt is equal to current (in amperes) multiplied by voltage (in volts).
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MQ Generator Handbook