SECTION I
Theory of Operation
Page 1.1
BP+ 10-150
2/95
1.1 General
The BalancedPower
Plus®
(BP+)
Uninterruptible Power System (UPS)
presented in this manual is a solid state, on-line system designed to provide high
quality, continuously filtered and conditioned ac power to computers, their
peripherals and/or other critical equipment loads. Most commonly, the UPS is
configured as a single, stand-alone unit. Fifteen (15) power ratings are available
from 10 to 300 kVA. Information contained herein is applicable to all power ratings
except where specified otherwise.
A single UPS is comprised of the following basic components:
Input transformer
Rectifier/Charger
Inverter
Static Bypass Switch
Bypass Breaker
Output Transformer
System Control Logic and Circuitry
Digital Monitoring Panel
Battery
DC Disconnect
A one-line diagram in Section II shows the relationship of these various
components.
1.2 Rectifier/Charger
The UPS input voltage from the utility is fed into the rectifier/charger
(usually referred to as the rectifier) which converts the ac to filtered, regulated dc
voltage. The dc is used to power the inverter and to recharge the batteries as
necessary. The assembly consists of an input circuit breaker, a transformer, and a
solid-state three-phase rectifier designed to eliminate even ordered harmonics. An
optional input filter reduces harmonics caused by rectifier switching. This prevents
the harmonics from affecting utility distribution.
