Alpha Technologies CXPS 48-1.2-225 48 Vdc - Manual (Page 20)

053-691-B1 Rev E Page 12 of 33
2.5.9 Soft start
A soft start feature, sometimes referred to as a “current walk-in”, is used to eliminate an instantaneous demand on
the AC input source. The soft start gradually ramps up the current limit from zero to the pre-determined setting
over a time interval of up to five seconds. The rectifier output voltage is ramped up from the minimum voltage to
the float voltage.
2.5.10 Start delay
The rectifier modules are equipped with a delay timer to sequentially start a series of modules to prevent
excessive generator loading during a start up. The controller can be used to set the time delay to between 1 and
120 seconds. The 1-second minimum delay allows the input capacitors to charge.
2.5.11 Current-limit/short circuit protection
The current-limit feature determines the maximum output current of the rectifier module, regardless of output
voltage or power. The maximum output current is limited to a constant value even during a short circuit. Current
limiting can be used to mate the rectifier output current ampacity to the needs of the load plus the batteries to
minimize excessive battery recharge currents.
The rectifier can sustain a short circuit at the output terminals indefinitely. The maximum short circuit current will
not exceed 105% of the rated full load current.
2.5.12 Power limiting
Each rectifier module is designed to limit the power output to a specified value. This enables more current to be
supplied at lower output voltages, and allows matching of output power to the demand of constant power loads,
which are often used in telecom equipment.
This feature may also be used for a faster recharge of flooded batteries that are connected in parallel with the
load. The current-limit function overrides the power-limit feature.
2.5.13 High voltage shutdown (HVSD)
The high voltage shutdown feature protects the load from over voltages originating from the rectifiers. It shuts the
offending rectifier module if its output voltage is above a preset limit. The red alarm (Module Fail) LED light
illuminates continuously. The rectifier will restart automatically once the overvoltage condition has passed.
However, if more than three over voltage conditions occur in one minute, the module will latch off and remain shut
down until it is reset via the controller.
2.5.14 Battery eliminator operation
A rectifier module maintains all its rated specifications (except where indicated) with or without a battery attached
in parallel with a load. However, if there is no battery or no other rectifier modules supplying DC voltages, there
will be no monitoring or control activity during an AC input power or input fuse failure.