Alpha Technologies APP 9022S - Manual (Page 12)

1. Introduction
016-537-B0-001 Rev. A
12
© 2002 TM
1.2 Theory of Operation
The APP SPS contains a ferroresonant transformer and a resonant capacitor. During
AC LINE operation, utility power is fed into the primary winding of the ferroresonant
transformer, T1. An AC capacitor, C1, forms the resonant circuit of the ferroresonant
transformer which provides excellent noise and spike attenuation, short circuit current
limiting, and output voltage regulation. Note: The ferroresonant transformer produces
a "quasi" square wave output which resembles a rounded square wave.
AC power enters the Service Power Supply where it is regulated (at the required
output voltage) and passed onto the load via the Service Power Inserter (SPI)
located inside the power supply enclosure. A switch, located on the SPI, toggles
output power from the power supply requiring service to the APP SPS.
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.
1.3 APP Service Power Supply Features
Output Current (Ammeter)
The Ammeter displays output current flowing from the power module to the
load. When there is no load at the output, the Ammeter reads zero.
Output Breaker
The AC output breaker protects the load from excessive durations of short
circuit current, or an out-of-phase (or buck) condition. If the front panel
ammeter reads zero, indicating no output to the load, this breaker must be
checked, and reset if necessary.
Input Breaker / Power Switch
The AC input breaker protects the Service Power Supply from short circuit
conditions, especially when it is used in conjunction with a generator during
outage conditions. If the unit does not turn ON when power is applied, first
verify that the unit is plugged into the convenience outlet and that the main
AC circuit breaker is in the ON position.
Output Power Indicator (9022) / Pilot Light (9015)
The Output Power Lamp displays the presence of output AC voltage.