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EX2100 User’s Guide GEH-6632 Chapter 3 Printed Wiring Boards Overview
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3-9
Power Supply Boards
The exciter power supply boards are as follows:
• IS200EPDM Exciter Power Distribution Module (EPDM)
• IS200EPBP Exciter Power Backplane (EPBP)
• IS200EPSM Exciter Power Supply Module (EPSM)
• DACA Module
EPDM Module
The EPDM provides the power for the control, I/O, and protection boards. It is
mounted on the side of the EPBP and accepts a 125 V dc supply from the station
battery, and one or two 115 V ac supplies. All supply inputs are filtered. Each ac
supply is rectified to 125 V dc in an ac to dc converter (DACA). The resulting two or
three dc voltages are diode coupled together to create the dc source supply,
designated as P125V and N125V. With the center grounded, these voltages are
nominally +62.5 V and –62.5 V to ground.
Any of the exciter power
supply modules can be
switched off from the EPDM.
Individual supply outputs to the exciter boards are fused. They have an on/off toggle
switch, and a green LED indicator to display supply power availability. These
outputs supply up to three EGPA boards, the EXTB board, and three EPSM modules
serving the three controllers. Outputs are wired to the EPBP for distribution. For
more information refer to Chapter 4.
EPBP Backplane
The EPBP holds three electrically isolated power supplies (EPSM) that supply power
to the M1, M2, and C controllers. It also holds three EGDM. EPBP accepts 125 V dc
from the adjacent EPDM, and distributes logic level power from the three EPSM to
the three controllers. Each power supply has an independent ON-OFF switch on the
EPDM. The EPSM modules interface to the backplane through DIN connectors. 70
V dc and 24 V dc power is distributed from the locking connectors at the top of the
backplane to the terminal boards. Refer to Figure 3-2. For more information refer to
Chapter 4 and GEI-100463.
EPSM Module
The EPSM converts 125 V dc from the EPDM into the voltages required for the
control system. There are three independent power supplies that supply power to
each of the controllers M1, M2, and C. These supplies are located in the power
supply module mounted below the control rack in the control cabinet.
The EPSM supplies +5 V dc, ±15 V dc, and +24 V dc to the controller. Power is also
supplied to modules external to the control rack as follows:
• ±24 V dc to power the EDEX de-excitation module, crowbar module, EGDM,
and EDCF
• Isolated +70 V dc for contact wetting to the EXTB and ECTB boards
For more information refer to Chapter 4 and GEI-100462.