1. INTRODUCTION
2
1.2
Theory of Operation
The XP Series Uninterruptible Power Supply consists of an XM Series power module,
a pole or ground-mount enclosure, and a set of gelled electrolyte, no maintenance batter-
ies. The power module contains a ferroresonant transformer, resonant capacitor, dual-
mode temperature-compensated battery charger, DC to AC converter (inverter), transfer /
isolation relay, and a main circuit module assembly containing the logic circuit.
1.2.1
AC (LINE) Operation
During AC LINE operation, utility power is routed into the primary winding of
ferroresonant transformer T1 and through the contacts of the transfer / isolation relay K101.
At the same time, power is directed to the auxiliary transformer T101 which provides power
for the control circuitry. A charger / inverter winding on transformer T1 supplies the battery
charger circuit. AC capacitor C1 forms the resonant circuit of ferroresonant transformer T1
which provides excellent noise and spike attenuation, short circuit current limiting, and
output voltage regulation. The ferroresonant transformer produces a "quasi" square wave
output which resembles a rounded square wave.
NOTE: WHEN MEASURING THE OUTPUT VOLTAGE OF FERRORESONANT
TRANSFORMERS, USE ONLY A TRUE RMS AC VOLTMETER. NON-RMS READING
METERS ARE CALIBRATED TO RESPOND TO PURE SINE WAVES AND WILL NOT
PROVIDE AN ACCURATE READING WHEN MEASURING A "QUASI" SQUARE WAVE
OUTPUT.
The XP Series Uninterruptible Power Supply
