Salicru SLC CUBE4, User Manual

65

11.  ANNEX III. GLOSSARY

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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.

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Bypass

.- Manual or automatic, this is the physical connection 

between the input of an electrical device and its output.

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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.

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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).

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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.

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GND

.- This stands for GROUND or EARTH and, as the name 

indicates, refers to the potential of the earth surface.

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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.

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Interface

.- In electronics, telecommunications and hard-

ware, an interface (electronics) is the port (physical circuit) 

through which signals are sent or received from one system 

or subsystem to another.

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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.

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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.

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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).

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Circuit breaker

.- A circuit breaker is a device capable 

of interrupting the electrical current of a circuit when it 

exceeds certain maximum values.

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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.

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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.

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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.

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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.

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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.

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SCR

.- Silicon controlled rectifier, commonly known as a 

thyristor, a 4-layer semiconductor device that works as an 

almost ideal switch.

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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.

SLC CUBE4

  - UNINTERRUPTIBLE POWER SUPPLY SYSTEM 

-

USER MANUAL