Theory Of Operation - Infinite TRANSTECTOR 700 AV/T Series Owner's Manual

7

THEORY OF OPERATION

The Series 700AV/T Power Line Conditioner provides the triple function of isolation, noise
attenuation and voltage regulation. The first two functions are provided by the power transformer,
where as the third function of voltage regulation is achieved through solid state thyristors (SCR's)
connected to taps on the power transformer. A microprocessor monitors and controls the overall
function of regulating the system.
The power transformer is manufactured with a unique method of shielding which produces very
low capacitive coupling between the primary and secondary. This low coupling provides excellent
attenuation of the common mode noise. In addition, special care is taken in the design of the transformer
to attenuate transverse-mode noise above 1000 Hz.
The power transformer has taps to which solid state switches (SCR's) are connected.
The voltage regulator incorporated in the Series 700AV/T Power Line Conditioner is microprocessor
controlled to achieve optimum correction time of input voltage sags and surges. The response time is
typically one (1/2) cycle for 100% correction, therefore, a very smooth switch takes place undetected
by computer equipment.
As the input voltage (building power) varies, the voltage available at each tap of the transformer
will also change. The amount of variation is dependant upon the input sag or surge, turns ratio and
transformer losses.
By selecting a particular tap voltage, the output can be kept within a tight range. The way in which
this is accomplished is that an electronic control card using a micro-processor continually monitors
the input voltage. When a voltage fluctuation occurs, which exceeds the limit of rated regulation
(typically ± 2%), the output is switched to another tap, that is within the required range. This "switch"
will be made at the next current zero crossing to allow for both leading and lagging power loads to be
connected to the conditioner.