TM 9-6115-669-13&P
1.14.7 Interaction of Components within the System.
Operating the EPP III with the loads or with the commercial power converter involves transferring
a variety of control and acknowledgment signals through the signal lines. The subparagraphs above
also provide detailed descriptions of the signals.
Synchronization
Synchronization involves measuring the R (L1) and S (L2) phase voltages on the bus bars (figure
1-13). Identical synchronization circuits are present for this purpose in the generators and in the
EPP III PDU, which are active simultaneously. During operation with the commercial power
converter, both bus bars 1 and 2 are linked through the power contactors and power cable. Power
contactors K1 and K40 are activated when synchronization is assured.
Control System for Parallel Generator Operation
The control lines required for parallel generator operation are looped from the two J9 connectors of
the generator connection panels through the PDU. The signals involved are those on J9 connector
pins F, G, H, J, P, R, S, T, U, X, Y, 2 (table 1-4). These signals are not used in the PDU.
Control System between EPP III, Commercial Power Converter, and ECS Load
These control signals and signal lines act between the generator and PDU control systems through
connector J9 (table 1-4), and then through connector J5 and the control cable to the ECS (table 1-5).
Operating with the Commercial Power Convetrter
For this operating mode, two additional cables must be connected to the PDU. Phase voltages R (L1)
and S (L2) are switched through the cable to J6 for synchronization purposes. The cable to J20 is
used to switch power contactor K40.
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