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ReFlex Power™
AC/DC I
2.4.6
The Mainframe distributes the input power through backplane connectors to
three groups of four slots connected in parallel. Each group is connected to a
separate pair of pins of the input connector (one line and return per connection);
the connector has six power pins plus ground. To properly size the current rating
of the disconnect device, the total load current that will be drawn from an input
line must be determined based on the location of modules within a Mainframe.
The backplane connector from which a module will draw input current is also
dependent on the width of the module. Table 2-2 presents the number of slots
that a particular module will occupy, to which slot the module will be connected to
draw input power, and the maximum current that the module will draw.
For example, a Mainframe with six HPDC modules (each 2U wide) would have
modules plugged into the following locations: slot 2, slot 4, slot 6, slot 8, slot 10,
and slot 12 (see Figure 2-5). The slots would be connected to the input
connector, as follows: line L1 connected to slots 2 and 4, line L2 connected to
slots 6 and 8, and line L3 connected to slots 10 and 12. If the modules supplied
full rated output power, and the AC input were three-phase, wye with nominal
230/400VAC, each input line would supply 10.8A.
As another example, a Mainframe with four AC power modules would have
modules plugged into the following locations: slot 3, slot 6, slot 9, and slot 12.
The slots would be connected to the input connector, as follows: line L1
connected to slot 3, line L2 connected to slot 6, and line L3 connected to slots 9
and 12. The input current would not be balanced from a three-phase source. If
the modules supplied full rated output power, and the AC input were three-phase,
wye with nominal 230/400VAC, lines L1 and L2 would each supply 5.4A, but line
L3 would supply 10.8A.
M380056-01 Rev L
O
NPUT
VERCURRENT
P
ROTECTION
Mainframe
2-15
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