Alpha Technologies Cordex HP CXRF 48-12kW - Manual (Page 14)

9400000-J0 Rev C 12
3.2 Rectifier Rear Panel
A single connector for shelf power and communications is located on the rear panel of each rectifier. The 12kW
rectifier has three connectors.
3.3 True Module Fail Alarm
The power modules have a “true” fail alarm that provides a true indication of the power module’s ability to source
current. When the module’s output current drops below 2.5% of the rated output, a low output current condition is
detected and the Module Fail detection circuit is activated. This circuit momentarily ramps up the output voltage
to determine if the module will source current. If no increase in current is detected, the Module Fail alarm is acti-
vated. The module will test once every 60 seconds for the condition until a current is detected. The output voltage
ramping ceases upon detection of Current1. A minimum 2.5% load is required to avoid the Ramp Test Fail alarm.
This can be provided with the parallel system battery. Activation of this alarm could indicate a failed module or a
failed load.
For Cordex rectifier systems without batteries, or with a very light load below 2.5% of the rated output, the ramp
test should be disabled to avoid nuisance alarms. The Ramp Test feature is enabled/disabled from the CXC
menu: Rectifiers > Configure Settings.
3.4 Heat Dissipation
Each rectifier module is equipped with at least one front-mounted fan. The fan runs when temperatures are above
0 ºC (32ºF). The air flow is front-to-rear with the exhaust air exiting at the back. The fan is a variable speed fan;
the speed is determined by the heatsink temperature and the load.
3.5 Over Temperature Protection
Component failure or a cooling airflow blockage can result in an excessive increase in temperature. During over-
temperature conditions, the rectifier limits the output power and the output current. If the temperature continues to
increase, the rectifier is shutdown. The rectifier restarts automatically when the temperature returns to a safe level.
3.6 Wide AC Range
A minor alarm is generated when the AC input voltage drops below its allowable limit.
3.6.1 4.0kW and 12kW
The rectifier output power is reduced linearly between 187 Vac and 150 Vac to 67% of the rated output power.
The unit delivers derated output power down to 90 Vac.
At 90 Vac, the module shuts down and does not restart until the AC voltage is greater than or equal to 150 Vac.
The restart voltage depends on the load current. A reduced load current may allow a restart input voltage as low
as 100 Vac.
For voltages above 277 Vac, the power factor and total harmonic distortion may be derated. Up to 320 Vac, the
rectifier will be operational and will not suffer any damage.
3.6.2 3.6kW
Rectifier output power is reduced linearly between 176Vac and 150Vac to 75% of the rated output power (the unit
will deliver derated output power down to 80Vac).
For voltages above 277 Vac, the power factor and total harmonic distortion may be derated. Up to 320 Vac, the
rectifier will be operational and will not suffer any damage.