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OnLine Power
2.4
FUNCTIONAL DESCRIPTION
Illustrations 2-4 thru 2-7 depict functional block diagrams of the Protector 3. These diagrams provide an
excellent tool for identifying the major building blocks within the Protector.
2.4.1
Main input circuit breaker - optional
The main input circuit breaker provides Protector 3 with incoming power isolation and input overcurrent
protection.
2.4.2
Input Contactor
Input contactor controls power applied to the unit. The microprocessor control circuit verifies that the UPS
is in "normal" and not at a "fault" condition and that the input voltage and frequency are within an
acceptable range. Only then it energizes the contactor closing coil via control transformer and fuse.
2.4.3
Input Inductors
The input inductors are a 3 phase input filter.
2.4.4
Inverter
When the AC input power is not available to power the load, the inverter converts the energy stored in the
battery bank to AC power to supply power to the load. The pulse width modulated (PWM) inverter utilizes
high speed, high efficiency IGBTs for fast response, sinusoidal power.
2.4.5
Battery charger
The battery charger converts AC power into regulated DC power to re-charge and to maintain the charge
on the battery bank. The charger is fully automatic with a current tapering feature so that battery damage
will be prevented in case of a charger malfunction or increased battery temperature. The charger is sized
to maintain a full charge even when the input voltage is at the low line limit for indefinite periods of time.
2.4.6
Battery
The battery bank, consists of 16, 24, 26 or 46, 12 Volt batteries, providing the reserve energy to sustain
the load when suitable AC input power is not present. The batteries are sealed, maintenance-free, VRLA
(Valve Regulated Lead Acid) construction.
2.4.7
DC Choke
The DC choke helps boost battery voltage to a higher internal DC bus voltage.
2.4.8
Output AC Inductor
The Output AC Inductor acts as a filter circuit component to reduce high frequency noise to the output
transformer.
2.4.9
Output Transformer
The Output Transformer performs two critical functions. First, it provides excellent common mode and
normal mode noise isolation of the load from the input or inverter power. Secondly, it provides voltage
transformation and tight regulation of the output voltage while the Protector is operating from its internal
inverter.
2-6
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