LTPS-UM-8007-01, Issue 1
Product Overview
SPX-CABFIN01, SPX-CABFIN04
November 9, 2001
3
Rectifier Modules
Rectifier output current remains equal to load current as long as load current does not exceed the rectifier output
capacity (nominally 25 amperes per rectifier; 50 amperes total). This mode of operation is known as float
charging. During normal operation, the battery does not furnish load current and remains fully charged. During
battery recharge following an AC power outage, or in the event of DC overload, the output current limiting circuit
prevents the increase of output current above the nominal 25 amperes per rectifier.
A fan assembly, at the rear of each rectifier module, supplies forced air ventilation. If a fan fails, local (faceplate)
and remote alarms are activated.
A Lorain
®
Battery Temperature Compensation Module (which must be secured in the field to battery No. 1 in the
battery drawer) automatically adjusts the output (float) voltage of each rectifier module, to maintain battery float
current as battery (ambient) temperature fluctuates. The temperature compensation module limits the rectifier
output voltage to 56.0 Vdc, and decreases rectifier output voltage with increasing temperature.
Alarm and Control Assembly
The Alarm and Control Assembly (ACA), at the far right of the rectifier shelf, continuously monitors rectifier
module DC output voltage.
High Voltage Shutdown
Each rectifier module has two High Voltage Shut-Down (HVSD) features that can disconnect the rectifier
modules if the output voltage rises above the limit (strapped at 56.0 Vdc) set by the temperature compensation
module.
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Selective HVSD and Restart—The selective HVSD is measured at the ACA front-panel (+) HVSD and (-)
VOLTS (X10) test points, and can be adjusted at the HVSD VOLT ADJ control. If the DC output voltage
exceeds the HVSD set point (normally 57.5 Vdc), the rectifier module which caused the high-voltage
condition shuts down immediately, provided that the rectifier module was delivering greater than 10% of its
full load. After approximately 4 seconds, the module automatically restarts. If the rectifier module output
voltage again exceeds the high voltage shutdown value within 5 minutes, the module shuts down and locks
out; the module must be manually reset. If there is not a high voltage condition within the 5-minute interval,
the restart circuit is reset and normal operation resumes.
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Non-Selective HVSD—If the rectifier module output voltage exceeds 59.5 Vdc (preset nonadjustable value),
the rectifier module shuts down immediately, regardless of the amount of load current being delivered before
the HVSD occurred.
DC Distribution Panel
The cabinet is equipped with a low voltage DC distribution panel having up to five circuit breakers. These circuit
breakers and the auxiliary fuses control DC power to the other cabinet equipment (described on the cabinet circuit
breaker decal).
B
ATTERIES
The SPX-CABFIN contains eight batteries which can be installed in a slide-out battery drawer at the cabinet base.
In the event of commercial power failure, batteries can supply up to 8 ampere-hours (Ah) of reserve power
(depending on the batteries installed).
The cabinet may be equipped with two series 12V strings of four batteries each, or one series 6V string of eight
batteries. Battery strings are connected by a connector bus on the drawer front wall; there are eight connectors per
