Alpha Technologies Cordex HP CXRF 48-12kW - Manual (Page 15)

13 9400000-J0 Rev C
3.7 AC Inrush/Transient Suppression
To prevent a surge on the AC inout line, the inrush current of a rectifier module is limited to the full load steady
state line current. Modules are also protected from input lightning and transient surges in accordance with IEEE/
ANSI C62.41 Category B3 standards.
3.8 Soft Start
A soft start feature is used to eliminate an instantaneous demand on the AC power source. A soft start, some-
times referred to as a “current walk-in”, works by gradually (up to five seconds) ramping up the current limit from
zero to the actual or defined customer setting. The rectifier output voltage is ramped from the minimum voltage to
the float voltage.
3.9 Start Delay
The rectifier modules are equipped with a delay timer to stagger-start a series of modules to prevent excessive
loading of generators upon start up. The built-in timer delays the switching on of the module by an interval (up
to 120 seconds), which is set in the CXC. A minimum one-second delay is preset to allow the input capacitors to
charge.
3.10 Current Limit/Short Circuit Protection
The current limit function determines the maximum output current limit of the rectifier module, regardless of the
output voltage or power. The maximum output current is limited to a constant value down to a short circuit condi-
tion. Current limiting can be used to mate the rectifier output current ampacity to the needs of the load and paral-
lel battery to minimize excessive battery recharge currents.
The rectifier will sustain a short circuit at the output terminals indefinitely. The maximum short circuit current will
not exceed 105% of the rated full load current.
3.11 Power Limiting
Each rectifier module is designed to limit the power output to the module specification. This enables more current
to be supplied at lower output voltages, and allows matching the output power to the demands of constant-power
loads often seen in telecom equipment.
This feature may also be used for a faster recharge of flooded batteries paralleled with the load.
NOTE:
The current limiting feature overrides the power-limiting feature.
3.12 High Voltage Shutdown (HVSD)
This feature protects the load from over-voltages originating in the rectifiers. The offending rectifier module is shut
down when a high output voltage condition occurs. The red Alarm (Module Fail) LED will illuminate. The module
will restart automatically. However, if more than three over-voltage conditions occur within one minute, the module
will latch off and remain shut down until it is reset by restarting the rectifier via the CXC.
3.13 Battery Eliminator Operation
Rectifier modules maintain all specifications (except where indicated) with or without a battery attached in paral-
lel to the output. However, if a battery or another module supplying DC voltage in parallel is not present, there will
be no monitoring or control activity during an AC power failure or input fuse failure.