SECTION 2 |
General Information
6
2.1. DEFINITIONS
The following definitions are used in this manual for explaining various electrical
concepts, specifications and operations:
Peak Value: It is the maximum value of electrical parameter like voltage / current.
RMS (Root Mean Square) Value: It is a statistical average value of a quantity that
varies in value with respect to time. For example, a pure sine wave that alternates
between peak values of Positive 325V and Negative 325V has an RMS value of 230
VAC. Also, for a pure sine wave, the RMS value = Peak value ÷ 1.414.
Voltage (V), Volts: It is denoted by “V” and the unit is “Volts”. It is the electrical force
that drives electrical current (I) when connected to a load. It can be DC (Direct
Current – flow in one direction only) or AC (Alternating Current – direction of flow
changes periodically). The AC value shown in the specifications is the RMS (Root
Mean Square) value.
Current (I), Amps, A: It is denoted by “I” and the unit is “Amperes“– shown as “A”. It
is the flow of electrons through a conductor when a voltage (V) is applied across it.
Frequency (F), Hz: It is a measure of the number of occurrences of a repeating event
per unit time. for example, cycles per second (or Hertz) in a sinusoidal voltage.
Efficiency, (
η
): This is the ratio of Power output ÷ Power Input.
Phase Angle, (
φ
): It is denoted by “
φ
”
and specifies the angle in degrees by which
the current vector leads or lags the voltage vector in a sinusoidal voltage. In a purely
inductive load, the current vector lags the voltage vector by Phase Angle (
φ
) = 90°. In
a purely capacitive load, the current vector leads the voltage vector by Phase Angle,
(
φ
) = 90°. In a purely resistive load, the current vector is in phase with the voltage
vector and hence, the Phase Angle, (
φ
) = 0°. In a load consisting of a combination
of resistances, inductances and capacitances, the Phase Angle (
φ
) of the net current
vector will be >0° <90° and may lag or lead the voltage vector.
Resistance (R), ohm, Ω: It is the property of a conductor that opposes the flow of
current when a voltage is applied across it. In a resistance, the current is in phase with
the voltage. It is denoted by “R” and its unit is “Ohm” - also denoted as “Ω”.
Inductive Reactance (X
L
), capacitive Reactance (X
C
) and Reactance (X): reactance is the
opposition of a circuit element to a change of electric current or voltage due to that
element’s inductance or capacitance. Inductive reactance (X
L
) is the property of a coil
of wire in resisting any change of electric current through the coil. It is proportional
to frequency and inductance and causes the current vector to lag the voltage vector
by Phase Angle (
φ
) = 90°. Capacitive reactance (X
C
) is the property of capacitive
elements to oppose changes in voltage. X
C
is inversely proportional to the frequency
Содержание PSI 1000-12/24
Страница 52: ...www samlex com www samlex solar com...
