Hardware reference guide

Pwr. & Grnding. Guide
35013379 11/2011 745
If these constraints are observed, then in a system of two or three redundant
supplies, one supply (it doesn’t matter which one) is hot-swappable. This is possible
because there is excess capacity in the N – 1 remaining supplies to source the
backplane current while the Nth supply is being swapped.
An obvious extension to this argument is that a single redundant power supply may
be used as a standalone supply (but the lowest cost solution will be achieved by
using a summable or standalone supply for this application).
Compatibility Issues of power supplies
z With the exception of standalone models, power supplies with the same model
number are always compatible when installed in the same backplane.
z
Do not use a standalone power supply in combination with any other supply in the
same backplane.
z
Do not mix different models of power supplies on the same backplane, except in
the following combinations:
CAUTION
Limits to Backplane Load
z If two 140CPS12420 power supplies are installed in the backplane, the
maximum backplane load available for redundant operation is 10 A.
z If three 140CPS12420 power supplies are installed in the backplane, the
maximum backplane load available for redundant operation is 20 A.
Use only like redundant power supplies except for 140CPS12420 which can be
mixed with one 140CPS22400 or one 140CPS42400.
z If one CPS12420 is installed with one 140CPS22400 or one 140CPS42400 in
the backplane, the maximum backplane load available for redundant operation
is 8 A.
z If one 140CPS12420 is installed with two 140CPS22400 or two 140CPS42400
in the backplane, the maximum backplane load available for redundant
operation is 16 A.
z If two 140CPS12420 are installed with one 140CPS22400 or one
140CPS42400 in the backplane, the maximum backplane load available for
redundant operation is 16 A.
Failure to follow these instructions can result in injury or equipment damage.