SECTION 2 |
General Information
2.1. DEFINITIONS
The following
are used in this manual for explaining various electrical
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
–
in one direction only) or AC (Alternating Current – direction of
changes peri-
odically). The AC value shown in the
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
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.
η
E
): This is the ratio of Power output ÷ Power Input.
Phase Angle, (φ): It is denoted by "φ
current vector leads or lags the voltage vector in a sinusoidal voltage. In a purely induc-
tive 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, induct-
ances and capacitances, the Phase Angle (φ) of the net current vector will be > 0° < 90°
and may lag or lead the voltage vector.
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6 | SAMLEX AMERICA INC.
6 | SAMLEX AMERICA INC.
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