Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
4.6 DETERMINING CHANNEL MODULE POWER REQUIREMENTS
To determine how much power the channel modules in a multiplexer shelf will draw, refer to Tables
4-1 and 4-2. The current draw at +5V, +15V and –15V for all IMUX 2000 channel modules,
Common Modules, OIAs and Module Adapters are given in these tables.
To use the tables, write down the number of modules of each type in the multiplexer shelf in the
"Number Per System" column. (If the multiplexer has a Repeater Shelf with no power supply modules,
be sure to include the channel modules in the Repeater Shelf. If the Repeater Shelf has its own power
supply modules, use Table 4-2 to determine its power requirements.) Multiply the “Number Per
System” column by the product of the voltage x current at +5V, +15V and –15V and enter the results
in the appropriate “Watts@”columns. Then calculate the watts/card, and enter the results in the last
column. When you are finished, add up all the totals to determine the total power consumption for the
shelf. If the current draw exceeds 4.0 Amps from the+5V supply, 0.75 Amps from the+15V supply, or
0.75 Amps from the–15V supply, additional power supply capacity is required.
4.7 POWER SUPPLY REDUNDANCY
IMUX 2000 Main Shelves and Repeater Shelves may be equipped with two power supply modules for
redundancy. If the primary supply fails, the redundant supply is automatically switched in to provide
uninterrupted multiplexer operation.
Note that the second supply is strictly a backup to the first, not an increase in available power. The
total shelf power is the individual capacity of either supply, not their sum. For example, a terminal
multiplexer Main Shelf equipped with two 50-watt power supplies would have a total of 48 watts
available for channel modules, not 98 watts.
If additional power supply capacity is needed in multiplexers equipped with Repeater Shelves, power
supply modules may be installed in the Repeater Shelves to power the channel modules located there.
4.8 APPLICATIONS WITH MAIN AND EXPANSION SHELVES
In applications using main and expansion shelves with dual power supplies in both shelves, make note
of the following recommendations:
1. Whenever possible, balance the heat loss in the main and expansion shelves by selecting which
cards go in each shelf. This spreads the heating between the two shelves and allows better
cooling.
2. Whenever a lower shelf exceeds 20W of draw, a 1U space should be left between shelves.
3. Whenever possible, it is better heatwise to have the power supplies only in the upper shelf and
use a power cable to the expansion shelf.
IMUX 2000E1 RFL Electronics Inc.
January 1, 2008 4-7 (973) 334-3100
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