Appendix C - Functional Operation
150-431-115-01, Revision 01
50
September 22, 1998
HLU-431 List 1E
P
OWER
C
ONSUMPTION
WITHOUT
D
OUBLERS
The three most important power parameters of an HLU are its maximum power consumption, its maximum power
dissipation, and its maximum current drain.
The Maximum Power Consumption is the total power that the HLU-431 consumes or draws from its
-48 V shelf power source. This parameter is needed when the HLU-431 is remotely located to its serving CO. It
determines the battery capacity required to maintain an eight-hour standby battery reserve for emergency
situations; thus limiting the maximum number of plugs per line unit’s remote enclosure.
The Maximum Current Drain is the maximum current drawn from the shelf power supply when it is at its
minimum voltage (-42.5 V). It determines the shelf fusing requirements.
Heat baffles should be placed between every other shelf, in racks containing more than two shelves. This
technique deflects the rack’s heat outward and reduces thermal stress on the plugs.
Power Consumption: Without Doublers
Maximum Power Dissipation:
•
Per Slot = 6 Watts
•
Per Shelf = 84 Watts (14 slots)
Maximum Power Consumption:
•
Per Slot = 14 Watts
•
Per Shelf = 196 Watts
Maximum Current Drain:
•
Per Slot = 0.38 Amps
•
Per Shelf = 5.3 Amps
The worst case conditions, under which these parameters were measured, include a 9,000 ft.,
AWG 26 loop, 60 mA of Customer Provided Equipment (CPE) current, a fully loaded 14-slot
shelf, and a -42.5 V shelf battery voltage with the HLU-431 4-character display “OFF.”