Tap Changing Regulator
A device that improves the regulation of an AC power source. The
regulator is placed between an AC power source and the load to be protected.
A tap-changing regulator has a special transformer with multiple outputs or
taps. Typically, one of the output taps provides a voltage equal to the
input voltage, while other taps provide various voltages which are a few
percent higher or lower than the input voltage. An automatic selector switch
chooses the tap which provides the voltage closest to the desired output
voltage. In operation, if the AC power source were to suddenly decrease in
voltage by 5% from nominal and remain at that voltage, then the Tap-Changing
Regulator would respond by choosing a transformer tap 5% higher than the
input voltage and would supply this corrected voltage to the load.
Tap-Changing Regulators are especially useful in situations where a site is
experiencing chronically high or low line voltage.
Thermocouple
A junction of two dissimilar metals that
produce a voltage when heated.
Three-Phase Power
Three separate
outputs from a single source with a phase differential of 120 electrical
degrees between any two adjacent voltages or currents. Mathematical
calculations with three phase power must allow for the additional power
delivered by the third phase. Remember, both single phase and three phase
have the same phase to phase voltages, therefore you must utilize the square
root of 3 in your calculations. For example, KVA equals volts times amps for
DC and for single phase. For three phase the formula is volts times the
square root of three times amps.
Torque
The turning effort or twist which a shaft
sustains when transmitting power.
Total Harmonic Distortion (THD)
The square root of the sum of the squares of the RMS harmonic voltages or
currents divided by the RMS fundamental voltage or current. Can also be
calculated in the same way for only even harmonics or odd harmonics.
Transformer
A static electrical
device which , by electromagnetic induction, regenerates AC power from one
circuit into another. Transformers are also used to change voltage from one
level to another. This is accomplished by the ratio of turns on the primary
to turns on the secondary (turns ratio). If the primary windings have twice
the number of windings as the secondary, the secondary voltage will be half
of the primary voltage.
Transient
A high amplitude, short duration pulse superimposed on
the normal voltage wave form or ground line.
Transient Response
The ability of
a power conditioner to respond to a change. Transient step load response is
the ability of a power conditioner to maintain a constant output voltage
when sudden load (current) changes are made.
Transmission Line
The conductors
used to carry electrical energy from one location to another.
Transverse Mode Noise
(Normal
mode)- An undesirable voltage which appears from line to line of a power
line.
