Salicru SLC CUBE 4 7.5 kVA Mode D'emploi page 144

14. ANNEX V. GLOSSARY.
AC.- Alternating current is electric current in which the
•
magnitude and direction vary cyclically. The waveform of the
most commonly used alternating current is that of a sine wave,
since this achieves a more efficient transmission of energy. In
certain applications, however, other periodic waveforms are
used, such as triangular or square.
Bypass.- Manual or automatic, this is the physical
•
connection between the input of an electrical device and
its output.
DC.- Direct current is the continuous flow of electrons through
•
a conductor between two points with different potential.
Unlike AC, in DC, electrical loads always circulate in the same
direction from the point of greatest potential to the lowest.
Although DC is commonly identified as a continuous current
(for example, that supplied by a battery), any current that
always maintains the same polarity is continuous.
DSP.- Digital signal processor. A DSP is a processor or
•
microprocessor-based system that has a set of instructions,
hardware and optimised software for applications that require
numerical operations at very high speed. Because of this, it
is especially useful for the processing and representation of
analogue signals in real time: in a system that works in this
way (real time) samples are usually received from an analogue/
digital converter (ADC).
Power factor.- The power factor, PF, of an AC circuit is defined
•
as the ratio between active power, P, and apparent power, S,
or as the cosine of the angle formed by the current and voltage
factors, designated in this case as cos f, where f is the value
of the angle.
GND.- This stands for GROUND or EARTH and, as the name
•
indicates, refers to the potential of the earth surface.
IGBT.- An insulated gate bipolar transistor (IGBT) is a
•
semiconductor device that is generally used as a controlled
switch in power electronics circuits. This device possesses
the characteristics of the gate signals of field effect transistors
with the capacity for high current and low saturation voltage
of the bipolar transistor, combining an isolated FET gate for
input and control and a bipolar transistor as a single switch in
a single device. The IGBT's excitation circuit is similar to that of
the MOSFET, while the conducting characteristics are similar
to those of the BJT.
Interface.- In electronics, telecommunications and hardware,
•
an interface (electronics) is the port (physical circuit) through
which signals are sent or received from one system or sub-
system to another.
kVA.- A volt-ampere is the unit used for apparent power in
•
electrical current. In DC, it is practically equal to real power
but, in AC, it can differ from this depending on the power factor.
LCD.- Liquid crystal display, a device invented by Jack Janning,
•
who was an employee of NCR. It is an electrical system for
data presentation formed by 2 transparent conductive layers
and a special crystalline material in the middle (liquid crystal)
which have the ability to orientate light as it passes through.
144
LED.- Light-emitting diode, a semiconductor device (diode)
•
that emits light that is almost monochromatic, that is to
say, it has a very narrow spectrum when it is polarised
directly and is penetrated by an electric current. The colour
(wavelength) depends on the semiconductor material used in
the construction of the diode, and can vary from ultraviolet,
passing through the visible light spectrum, to infrared, the
latter called IRED (infra-red emitting diode).
Circuit breaker.- A circuit breaker is a device capable of
•
interrupting the electrical current of a circuit when it exceeds
certain maximum values.
Disconnect switch.- Mechanical disconnecting device with
•
two alternative positions with a separation between contacts
that satisfies the minimum physical spacing between the two
parts of the mains where it is located. In case of failure of the
circuit in which it is located, it opens its contacts automatically,
thus isolating the failure. They can open or close circuits only
when they are without loads.
Online mode.- A device is said to be online when it is
•
connected to a system, is operative, and normally has its
power supply connected.
Inverter.- An inverter is a circuit used to convert DC into AC.
•
The function of an inverter is to change a DC input voltage
to a symmetrical AC output voltage, with the magnitude and
frequency desired by the user or designer.
Rectifier.- In electronics, a rectifier is the element or circuit
•
that converts AC into DC. This is done by using rectifier diodes,
whether solid state semiconductors, vacuum valves or gaseous
valves, such as those containing mercury vapour. Depending
on the characteristics of the AC power that they use, they are
classified as single-phase when they are powered by a mains
phase or three-phase when they are powered by three phases.
Depending on the type of rectification, they can be half wave
when only one of the half cycles of the current is used or full
wave when both half cycles are used.
Relay.- A relay is an electromechanical device that functions
•
as a switch controlled by an electrical circuit in which, by
means of an electromagnet, a set of one or several contacts
is activated to enable other independent electrical circuits to
be opened or closed.
SCR.- Silicon controlled rectifier, commonly known as a thy-
•
ristor, a 4-layer semiconductor device that works as an almost
ideal switch.
THD.- Total harmonic distortion. Harmonic distortion occurs
•
when the output signal of a system does not equal the signal
that entered it. This lack of linearity affects the waveform
because the device has introduced harmonics that were not
in the input signal. Since they are harmonic, that is to say,
multiples of the input signal, this distortion is not so dissonant
and is less easy to detect.
SALICRU