IQH3A IQ 3U Modular Enclosure
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Installation
Issue 2 Rev 2
Page 25
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2014 Snell Limited
3.11 Power Supply and Module Slot Locations
The dual power supplies of the IQH3A 3U Enclosure are designed to accept one or two
SPX0149 power supplies with independent IEC320 mains inlets.
Individually, each PSU module is capable of powering the IQM 3U frame containing any
combination of IQ-1A modules subject to Configuration Rules. When two units are installed
the operation of the whole frame becomes protected against single-instance power failures.
The manufacturer specifies a maximum of 50 mating cycles.
Monitoring circuitry built in to each PSU reports power failures via isolated relay contacts on
the `STATUS' connector (9-pin D-type, female) on the frame rear panel and two bi-color LEDs
on the front of each power supply.
The bi-color LEDs on the PSU front panels are green if the PSU is supplying power to the
rack, and turn red if the associated regulation unit has failed.
The LEDs are also red if the mains power to the unit has failed or if the unit is switched to
standby, provided that the other PSU is functioning.
Within the SPX0149 power supplies the positive and negative rails are independently
regulated and have no minimum load current requirements.
The DC outputs of the SPX0149 power supplies have series Schottky diodes that allow direct
connection of multiple units on one power bus.
Additional components adjust the regulation so that the power supplies will attempt to share
the load current requirements. The balance of current sharing between supplies is subject to
variation of the basic regulation of the PSUs. With two PSUs the unit with the higher output
voltage will contribute more current to the load.
PSUs
Gateway Card
Module Slots 1 to 16
